matsim-org/matsim-libs
Nov 2024 – Oct 2025
11 Months active
Languages Used
Java
Technical Skills
Algorithm OptimizationBackend DevelopmentData AnalysisJava DevelopmentSimulationSimulation Analysis
Nico Kühnel
PROFILE
Nico Kühnel
Nico Kühnel developed and enhanced core features for the matsim-org/matsim-libs repository, focusing on dynamic ride-sharing, routing accuracy, and operational reliability. He architected modular systems for DRT scheduling, zone-based analytics, and reservation management, applying advanced Java and AWS integration to support cloud-based workflows and robust simulation IO. His work included refactoring pathfinding algorithms for turn restrictions, centralizing constraints and configuration, and improving shift and charging task management. By emphasizing maintainable code, encapsulation, and testability, Nico addressed complex scheduling, capacity, and error-handling challenges, resulting in more flexible, scalable, and resilient simulation infrastructure for multi-market mobility scenarios.
Overall Statistics
Feature vs Bugs
64%Features
Repository Contributions
85Total
Bugs
15
Commits
85
Features
27
Lines of code
24,572
Activity Months11
Your Network
26 peopleSame Organization
@moia.io1
Work History
October 2025
3 Commits • 1 Features
Oct 1, 2025October 2025 (matsim-org/matsim-libs) summary: Delivered two targeted updates to DRT operations that drive business value in dynamic transit planning, plus resilience improvements to handle operational hiccups without disruption. Key features delivered include DRT Operations and Time Window Enhancements that make constraints relative to the earliest departure, enabling more flexible routing, improved offer acceptance, and capacity-aware scheduling; and Graceful Handling of Vehicle Checkout Failures that logs a warning instead of throwing to maintain operation continuity during temporary checkout issues. These changes were implemented via commits 10405b0018ca9ee89e93a1d7d64240d6994e6c70 (make drt constrains relative again), 55af20e995704136ac61ed10d866107d5f76ebb3 (feat(drt-extensions): operation facility with capacity management + condensed shift starts), and 61e093a2cd9c9c3f1424e577e3b98ecbcda940fa (relax operation facility checkout).
3 Commits • 1 Features
Oct 1, 2025October 2025 (matsim-org/matsim-libs) summary: Delivered two targeted updates to DRT operations that drive business value in dynamic transit planning, plus resilience improvements to handle operational hiccups without disruption. Key features delivered include DRT Operations and Time Window Enhancements that make constraints relative to the earliest departure, enabling more flexible routing, improved offer acceptance, and capacity-aware scheduling; and Graceful Handling of Vehicle Checkout Failures that logs a warning instead of throwing to maintain operation continuity during temporary checkout issues. These changes were implemented via commits 10405b0018ca9ee89e93a1d7d64240d6994e6c70 (make drt constrains relative again), 55af20e995704136ac61ed10d866107d5f76ebb3 (feat(drt-extensions): operation facility with capacity management + condensed shift starts), and 61e093a2cd9c9c3f1424e577e3b98ecbcda940fa (relax operation facility checkout).
October 2025
September 2025
1 Commits • 1 Features
Sep 1, 2025September 2025: Delivered a generic AbstractReservationManager in matsim-libs/common contrib, introduced as a centralized reservation core. Extended by ChargerReservationManager to consolidate charger reservation logic and prepare for additional scenarios. This refactor reduces duplication, improves maintainability, and enables future extension for reservation types across modules. The change is recorded in commit 9562cf96b96cf60b6cf1ed0e3efca15e8becde08 (#4260).
September 2025
1 Commits • 1 Features
Sep 1, 2025September 2025: Delivered a generic AbstractReservationManager in matsim-libs/common contrib, introduced as a centralized reservation core. Extended by ChargerReservationManager to consolidate charger reservation logic and prepare for additional scenarios. This refactor reduces duplication, improves maintainability, and enables future extension for reservation types across modules. The change is recorded in commit 9562cf96b96cf60b6cf1ed0e3efca15e8becde08 (#4260).
August 2025
11 Commits • 4 Features
Aug 1, 2025August 2025 (2025-08) — Delivered architecture-driven DRT enhancements and reliability fixes in matsim-libs, reducing cross-module coupling, enabling easier extension, and improving ride-assignment efficiency. Key outcomes include the DRT Schedule Inquiry abstraction, centralized DrtRouteConstraints with per-request rejection, enhanced StopWaypoint system with a factory for flexible stops, shift scheduling reliability fixes, and idle-time optimization for EmptyVehicleRelocator. These changes strengthen operational robustness, support future DRT extensions, and translate into more predictable scheduling and better resource utilization.
11 Commits • 4 Features
Aug 1, 2025August 2025 (2025-08) — Delivered architecture-driven DRT enhancements and reliability fixes in matsim-libs, reducing cross-module coupling, enabling easier extension, and improving ride-assignment efficiency. Key outcomes include the DRT Schedule Inquiry abstraction, centralized DrtRouteConstraints with per-request rejection, enhanced StopWaypoint system with a factory for flexible stops, shift scheduling reliability fixes, and idle-time optimization for EmptyVehicleRelocator. These changes strengthen operational robustness, support future DRT extensions, and translate into more predictable scheduling and better resource utilization.
August 2025
July 2025
7 Commits • 3 Features
Jul 1, 2025July 2025 (2025-07) — Matsim-libs delivered key reliability and cloud-readiness improvements for matsim-org/matsim-libs. This month focused on enforcing DRT ride duration maximums, strengthening IO robustness, integrating AWS S3 for inputs/outputs, and fixing a charging task removal edge case. The changes improve scheduling fidelity, reduce runtime errors at shift boundaries, enable cloud-based data flows, and enhance observability.
July 2025
7 Commits • 3 Features
Jul 1, 2025July 2025 (2025-07) — Matsim-libs delivered key reliability and cloud-readiness improvements for matsim-org/matsim-libs. This month focused on enforcing DRT ride duration maximums, strengthening IO robustness, integrating AWS S3 for inputs/outputs, and fixing a charging task removal edge case. The changes improve scheduling fidelity, reduce runtime errors at shift boundaries, enable cloud-based data flows, and enhance observability.
May 2025
10 Commits • 2 Features
May 1, 2025February-May monthly summary for matsim-libs (2025-05). Focused on delivering routing accuracy improvements, DRT analytics enhancements, and improved operational diagnostics with an emphasis on business value and cross-scenario robustness.
10 Commits • 2 Features
May 1, 2025February-May monthly summary for matsim-libs (2025-05). Focused on delivering routing accuracy improvements, DRT analytics enhancements, and improved operational diagnostics with an emphasis on business value and cross-scenario robustness.
May 2025
April 2025
8 Commits • 2 Features
Apr 1, 2025April 2025 (2025-04) — Delivered key configurability, routing accuracy, and code-quality improvements in matsim-libs that strengthen production reliability and multi-market applicability for DRT/DVRP workloads. Business value centers on flexible zone definitions, precise travel-time calculations, and robust scheduling of unscheduled requests, underpinned by maintainable code. Key features delivered: - Configurable Zone Systems and Travel Time Matrix: Introduced independent zone systems for analysis, rebalancing, and the DVRP travel-time matrix; enabled a configurable zone system for the adaptive travel time matrix. Commits include 26b7d14ae33927df6cd24657146d793a0625e5e2 and 00b43850b637b212b17f2ccc1f9b5b1acfd7521f. - Routing System Refactor: Link-based Path Calculations: Refactored routing to operate on links rather than nodes to improve accuracy with turn restrictions and network connectivity. Commit: c1b7546b1548e5bfb7ac6d93d29fb86621ecb13d. Major bugs fixed: - Unscheduled Request Handling Improvement: ComplexRequestUnscheduler now uses the vehicle's schedule directly, enhancing how unscheduled requests are located and replaced. Commit: 9bcea91820f047bbb36a9f25aaf47090f2df212c. - Deprecation Warning for zoneTargetLinkSelection: Added a user warning to inform that the configuration is deprecated and will be ignored, guiding migration to rebalancing parameters. Commit: 1c1fa658e902b31cce6706ca502d06ca9faad00b. - Code Quality and Encapsulation Improvements (DRT and FISS): Refactored DRT config accessors to getters/setters and encapsulated FISS config fields; included minor typo fixes. Commits: 18893098f7452af89bbe4d6c677d5dc8b5c866ee, 2f1049ed0bee0f4f1f26cfbfd7c07dbd3fcce370, 743fa700af243a1e6c805ace3d14bdc9880dcc83. Overall impact and accomplishments: - Increased configurability and routing accuracy enable flexible deployments across markets and more reliable travel-time calculations. - Improved unscheduled-request handling reduces operational risk and downtime when requests cannot be immediately scheduled. - Clear deprecation warnings and encapsulated configurations boost maintainability, test reliability, and onboarding speed for future features. Technologies/skills demonstrated: - Advanced configuration management, link-based routing algorithms, and domain-specific refactoring in a Java/Kotlin ecosystem; emphasis on DRT, DVRP, and FISS modules; commitment hygiene and typo fixes to improve code quality and test stability.
April 2025
8 Commits • 2 Features
Apr 1, 2025April 2025 (2025-04) — Delivered key configurability, routing accuracy, and code-quality improvements in matsim-libs that strengthen production reliability and multi-market applicability for DRT/DVRP workloads. Business value centers on flexible zone definitions, precise travel-time calculations, and robust scheduling of unscheduled requests, underpinned by maintainable code. Key features delivered: - Configurable Zone Systems and Travel Time Matrix: Introduced independent zone systems for analysis, rebalancing, and the DVRP travel-time matrix; enabled a configurable zone system for the adaptive travel time matrix. Commits include 26b7d14ae33927df6cd24657146d793a0625e5e2 and 00b43850b637b212b17f2ccc1f9b5b1acfd7521f. - Routing System Refactor: Link-based Path Calculations: Refactored routing to operate on links rather than nodes to improve accuracy with turn restrictions and network connectivity. Commit: c1b7546b1548e5bfb7ac6d93d29fb86621ecb13d. Major bugs fixed: - Unscheduled Request Handling Improvement: ComplexRequestUnscheduler now uses the vehicle's schedule directly, enhancing how unscheduled requests are located and replaced. Commit: 9bcea91820f047bbb36a9f25aaf47090f2df212c. - Deprecation Warning for zoneTargetLinkSelection: Added a user warning to inform that the configuration is deprecated and will be ignored, guiding migration to rebalancing parameters. Commit: 1c1fa658e902b31cce6706ca502d06ca9faad00b. - Code Quality and Encapsulation Improvements (DRT and FISS): Refactored DRT config accessors to getters/setters and encapsulated FISS config fields; included minor typo fixes. Commits: 18893098f7452af89bbe4d6c677d5dc8b5c866ee, 2f1049ed0bee0f4f1f26cfbfd7c07dbd3fcce370, 743fa700af243a1e6c805ace3d14bdc9880dcc83. Overall impact and accomplishments: - Increased configurability and routing accuracy enable flexible deployments across markets and more reliable travel-time calculations. - Improved unscheduled-request handling reduces operational risk and downtime when requests cannot be immediately scheduled. - Clear deprecation warnings and encapsulated configurations boost maintainability, test reliability, and onboarding speed for future features. Technologies/skills demonstrated: - Advanced configuration management, link-based routing algorithms, and domain-specific refactoring in a Java/Kotlin ecosystem; emphasis on DRT, DVRP, and FISS modules; commitment hygiene and typo fixes to improve code quality and test stability.
March 2025
16 Commits • 4 Features
Mar 1, 2025March 2025 monthly summary for matsim-libs highlights reliability, modularity, and expanded DRT capabilities. Key outcomes include end-of-iteration demand consolidation, end-of-shift relocation options with pre-booked insertion heuristics, enhanced DRT shift scheduling and EV charging task management, and DI-based shift assignment to improve modularity and testability. Critical stability fixes for prebooked agent cleanup prevent processing of non-existent agents and avoid stuck iterations. Minor documentation fix and configuration/data management improvements further strengthened maintainability. These changes deliver tangible business value through more robust simulations, faster iteration cycles, and safer deployment of DRT features.
16 Commits • 4 Features
Mar 1, 2025March 2025 monthly summary for matsim-libs highlights reliability, modularity, and expanded DRT capabilities. Key outcomes include end-of-iteration demand consolidation, end-of-shift relocation options with pre-booked insertion heuristics, enhanced DRT shift scheduling and EV charging task management, and DI-based shift assignment to improve modularity and testability. Critical stability fixes for prebooked agent cleanup prevent processing of non-existent agents and avoid stuck iterations. Minor documentation fix and configuration/data management improvements further strengthened maintainability. These changes deliver tangible business value through more robust simulations, faster iteration cycles, and safer deployment of DRT features.
March 2025
February 2025
9 Commits • 2 Features
Feb 1, 2025February 2025 monthly summary for matsim-libs: Delivered two major features that enhance routing reliability and maintainability in turn-constrained networks and in core pathfinding. Turn Restrictions Robustness and Accuracy improved routing correctness by consolidating colored nodes, preserving attributes when cleaning turn restriction networks, and ensuring correct coming-from logic, enabling more trustworthy simulations in complex networks. Pathfinding Core Refactor and Robustness modernized the path calculation pipeline by using node/link iterators, removing the parallel-links verification step, and tidying naming/formatting to improve clarity, encapsulation, and robustness. Major bug fixes included addressing a turn restriction related bug in LeastCostPathTree and updating the turn restriction network cleaner, reducing edge-case failures in routing. These efforts have strengthened routing confidence, reduced maintenance burden, and improved overall simulation reliability. Technologies/skills demonstrated include Java refactoring, iterator-based design, encapsulation, code hygiene, and targeted debugging across a large codebase.
February 2025
9 Commits • 2 Features
Feb 1, 2025February 2025 monthly summary for matsim-libs: Delivered two major features that enhance routing reliability and maintainability in turn-constrained networks and in core pathfinding. Turn Restrictions Robustness and Accuracy improved routing correctness by consolidating colored nodes, preserving attributes when cleaning turn restriction networks, and ensuring correct coming-from logic, enabling more trustworthy simulations in complex networks. Pathfinding Core Refactor and Robustness modernized the path calculation pipeline by using node/link iterators, removing the parallel-links verification step, and tidying naming/formatting to improve clarity, encapsulation, and robustness. Major bug fixes included addressing a turn restriction related bug in LeastCostPathTree and updating the turn restriction network cleaner, reducing edge-case failures in routing. These efforts have strengthened routing confidence, reduced maintenance burden, and improved overall simulation reliability. Technologies/skills demonstrated include Java refactoring, iterator-based design, encapsulation, code hygiene, and targeted debugging across a large codebase.
January 2025
10 Commits • 2 Features
Jan 1, 2025Concise monthly summary for 2025-01 focusing on business value and technical achievements. Delivered targeted routing and data-structural improvements in matsim-libs, with performance optimizations and API correctness fixes.
10 Commits • 2 Features
Jan 1, 2025Concise monthly summary for 2025-01 focusing on business value and technical achievements. Delivered targeted routing and data-structural improvements in matsim-libs, with performance optimizations and API correctness fixes.
January 2025
December 2024
8 Commits • 4 Features
Dec 1, 2024December 2024 performance highlights for matsim-libs: DRT routing robustness improved with Detour Constraints including a minimum detour, removal of a misleading consistency check, and validation ensuring min detour < max detour. SpatialRequestFleetFilter added to optimize DRT/ride-sharing vehicle selection via spatial proximity filtering and integration into request handling and QSim. Noise simulation gained configurable flexibility with a dedicated flag to enable/disable reflection calculations independently of shielding. Network integrity strengthened through improved handling of disallowed links during merging and preservation of turn restrictions, with a Replacement tracking mechanism for traceability. These changes collectively improve reliability, scalability, and modeling fidelity, delivering tangible business value through better routing decisions, faster dispatch, and more accurate network state after merges.
December 2024
8 Commits • 4 Features
Dec 1, 2024December 2024 performance highlights for matsim-libs: DRT routing robustness improved with Detour Constraints including a minimum detour, removal of a misleading consistency check, and validation ensuring min detour < max detour. SpatialRequestFleetFilter added to optimize DRT/ride-sharing vehicle selection via spatial proximity filtering and integration into request handling and QSim. Noise simulation gained configurable flexibility with a dedicated flag to enable/disable reflection calculations independently of shielding. Network integrity strengthened through improved handling of disallowed links during merging and preservation of turn restrictions, with a Replacement tracking mechanism for traceability. These changes collectively improve reliability, scalability, and modeling fidelity, delivering tangible business value through better routing decisions, faster dispatch, and more accurate network state after merges.
November 2024
2 Commits • 2 Features
Nov 1, 2024Monthly summary for 2024-11 focused on delivering high-value features in matsim-libs with accompanying tests, improving configurability, observability, and software quality. The work aligns with product goals of configurable zone-level policies and enhanced DR wait-time analytics, driving better operational efficiency and service reliability.
2 Commits • 2 Features
Nov 1, 2024Monthly summary for 2024-11 focused on delivering high-value features in matsim-libs with accompanying tests, improving configurability, observability, and software quality. The work aligns with product goals of configurable zone-level policies and enhanced DR wait-time analytics, driving better operational efficiency and service reliability.
November 2024
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Quality Metrics
Correctness87.6%
Maintainability87.8%
Architecture84.0%
Performance77.8%
AI Usage20.0%
Skills & Technologies
Programming Languages
Java
Technical Skills
API DesignAPI DevelopmentAPI IntegrationAWSAgent-Based ModelingAlgorithm DesignAlgorithm OptimizationAlgorithm RefactoringBackend DevelopmentBug FixingCapacity ManagementCode CleanupCode GenericsCode OrganizationCode Refactoring
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