Posts on Gabe Fierro

Validating ASHRAE 223P models

Thu, 05 Mar 2026 00:00:00 +0000

Note: I’ll be using my ontoenv tool to build this post

The ASHRAE 223P standard defines a set of SHACL shapes for validating building models. This post explains how to use those shapes to validate a building model, and also how to handle the ontology dependencies that the 223P shapes have.

Ontology Dependencies

A shapes graph contains a set of SHACL shapes that define the validation rules for a particular domain. Ontologies like ASHRAE 223P contain shapes which govern the structure and semantics of models; I’ll use “shapes graph” and “ontology” interchangeably here, but the important thing is that the graph contains SHACL shapes that we want to use for validation.

Temporary Postgres Databases

Tue, 03 Mar 2026 00:00:00 +0000

When teaching my undergraduate database course, I often have the need for writing little “throwaway” SQL tables and queries to help illustrate concepts or to test out a feature. Connecting to the “real” course server is inconvenient for a number of reasons: there is too much friction with my password manager to get the right login for the database, I have to make sure I’m on the right WiFi network (thanks to new IT policies), and I’d like to be able to demonstrate queries/actions that may cause problems for the course server without worrying about breaking anything.

My shortest Brick validation+inference script yet

Thu, 19 Feb 2026 00:00:00 +0000

My evenings these past few weeks have been spent working on ontoenv (a dev environment manager for ontologies) and shifty (a vibe-coded SHACL implementation). They are finally at the stage where I can get a short script working that does both inference and validation of a building model against the 223P SHACL shapes, and I’m pretty happy with how it looks!

The example model needs an `owl:imports` statement:

@prefix owl: <http://www.w3.org/2002/07/owl#> .

<http://example.com/ontoenv-example/> a owl:Ontology ;
 owl:imports <https://brickschema.org/schema/1.4/Brick> .

# etc... rest of your model

Here’s the short version of the script:

223P Validation Example (improved!)

Thu, 04 Dec 2025 00:00:00 +0000

I recommend installing uv to handle Python dependencies and versions.

Here’s the new and improved script for doing 223P validation+inference in Python. This uses the new OntoEnv API to manage ontology dependencies, and I’m pretty happy with how it looks now. (I have one more simplifying change to make to the API that I’ll include in the next release; I’d like to just write s223_with_dependencies = env.get_closure(s223_id) to both get the ontology and its dependencies in one step.)

Making Your Academic Portfolio Website

Wed, 21 May 2025 09:40:12 -0600

Graduate students — especially PhD students — should have an up-to-date academic portfolio website outside of a Google Scholar or LinkedIn profile. This post is a short guide to how to make a portfolio site and what to include on it. I’ll be linking to external documents and how-tos as much as possible to avoid having to repeat information that is best maintained by the original authors.

This post is just a starting point. It contains the “breadcrumbs” to point you in the right direction for making a portfolio site. Send me an email if there is anything I should add or change!

Defining HVAC Loops

Sun, 23 Mar 2025 00:00:00 +0000

This is an in-progress post and may contain some errors or incomplete information.

Here’s a specific example of a simple HVAC system in 223P:

Expand for Turtle definition of the 223P model

@prefix s223: <http://data.ashrae.org/standard223#> .
@prefix qudt: <http://qudt.org/schema/qudt/> .
@prefix qudtqk: <http://qudt.org/vocab/quantitykind/> .
@prefix unit: <http://qudt.org/vocab/unit/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix ex: <http://example.com/hvac/> .

<http://example.com/hvac> a owl:Ontology ;
 owl:imports <http://data.ashrae.org/standard223/1.0/model/all> .

# Air Handling Unit (AHU) and its connections
ex:AHU a s223:AirHandlingUnit ;
 s223:hasConnectionPoint ex:AHU_Inlet1, ex:AHU_Inlet2;
 s223:hasConnectionPoint ex:AHU_Outlet .

ex:AHU_Inlet1 a s223:InletConnectionPoint ;
 s223:cnx ex:Return_Duct1 ;
 s223:isConnectionPointOf ex:AHU ;
 s223:hasMedium s223:Fluid-Air .

ex:AHU_Inlet2 a s223:InletConnectionPoint ;
 s223:cnx ex:Return_Duct2 ;
 s223:isConnectionPointOf ex:AHU ;
 s223:hasMedium s223:Fluid-Air .

ex:AHU_Outlet a s223:OutletConnectionPoint ;
 s223:cnx ex:Supply_Duct ;
 s223:isConnectionPointOf ex:AHU ;
 s223:hasMedium s223:Fluid-Air .

# Supply Main Duct connections
ex:Supply_Duct a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:AHU_Outlet, ex:VAV1_Inlet, ex:VAV2_Inlet .

# return ducts
ex:Return_Duct1 a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:Room1_Outlet, ex:AHU_Inlet1 .

# VAV 1 and its internal components
ex:VAV1 a s223:SingleDuctTerminal ;
 s223:contains ex:VAV1_Damper, ex:Heating_Coil1 ;
 s223:hasConnectionPoint ex:VAV1_Inlet, ex:VAV1_Outlet .

ex:VAV1_Inlet a s223:InletConnectionPoint ;
 s223:isConnectionPointOf ex:VAV1 ;
 s223:cnx ex:Supply_Duct ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV1_Outlet a s223:OutletConnectionPoint ;
 s223:isConnectionPointOf ex:VAV1 ;
 s223:cnx ex:Supply_Duct ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV1_Damper a s223:Damper ;
 s223:hasConnectionPoint ex:VAV1_Damper_In, ex:VAV1_Damper_Out .

ex:VAV1_Damper_In a s223:InletConnectionPoint ;
 s223:mapsTo ex:VAV1_Inlet ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV1_Damper_Out a s223:OutletConnectionPoint ;
 s223:isConnectionPointOf ex:VAV1_Damper ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV1_Damper_Coil_Duct a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:VAV1_Damper_Out, ex:Heating_Coil1_In .

ex:Heating_Coil1 a s223:HeatingCoil ;
 s223:hasConnectionPoint ex:Heating_Coil1_In, ex:Heating_Coil1_Out .

ex:Heating_Coil1_In a s223:InletConnectionPoint ;
 s223:isConnectionPointOf ex:Heating_Coil1 ;
 s223:hasMedium s223:Fluid-Air .

ex:Heating_Coil1_Out a s223:OutletConnectionPoint ;
 s223:mapsTo ex:VAV1_Outlet ;
 s223:hasMedium s223:Fluid-Air .

# Room 1 and its connection
ex:Room1 a s223:PhysicalSpace ;
 s223:encloses ex:Room1HVAC .

ex:Room1HVAC a s223:DomainSpace ;
 s223:hasDomain s223:Domain-HVAC ;
 s223:hasConnectionPoint ex:Room1_Inlet, ex:Room1_Outlet .

ex:Room1_Inlet a s223:InletConnectionPoint ;
 s223:isConnectionPointOf ex:Room1HVAC ;
 s223:cnx ex:Supply_Duct_Room1 ;
 s223:hasMedium s223:Fluid-Air .

ex:Room1_Outlet a s223:OutletConnectionPoint ;
 s223:isConnectionPointOf ex:Room1HVAC ;
 s223:cnx ex:Return_Duct1 ;
 s223:hasMedium s223:Fluid-Air .

# Supply Duct to Room 1
ex:Supply_Duct_Room1 a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:VAV1_Outlet, ex:Room1_Inlet .

####### VAV 2 

# return ducts
ex:Return_Duct2 a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:Room2_Outlet, ex:AHU_Inlet2 .

# VAV 2 and its internal components
ex:VAV2 a s223:SingleDuctTerminal ;
 s223:contains ex:VAV2_Damper, ex:Heating_Coil2 ;
 s223:hasConnectionPoint ex:VAV2_Inlet, ex:VAV2_Outlet .

ex:VAV2_Inlet a s223:InletConnectionPoint ;
 s223:isConnectionPointOf ex:VAV2 ;
 s223:cnx ex:Supply_Duct ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV2_Outlet a s223:OutletConnectionPoint ;
 s223:isConnectionPointOf ex:VAV2 ;
 s223:cnx ex:Supply_Duct ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV2_Damper a s223:Damper ;
 s223:hasConnectionPoint ex:VAV2_Damper_In, ex:VAV2_Damper_Out .

ex:VAV2_Damper_In a s223:InletConnectionPoint ;
 s223:mapsTo ex:VAV2_Inlet ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV2_Damper_Out a s223:OutletConnectionPoint ;
 s223:isConnectionPointOf ex:VAV2_Damper ;
 s223:hasMedium s223:Fluid-Air .

ex:VAV2_Damper_Coil_Duct a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:VAV2_Damper_Out, ex:Heating_Coil2_In .

ex:Heating_Coil2 a s223:HeatingCoil ;
 s223:hasConnectionPoint ex:Heating_Coil2_In, ex:Heating_Coil2_Out .

ex:Heating_Coil2_In a s223:InletConnectionPoint ;
 s223:isConnectionPointOf ex:Heating_Coil2 ;
 s223:hasMedium s223:Fluid-Air .

ex:Heating_Coil2_Out a s223:OutletConnectionPoint ;
 s223:mapsTo ex:VAV2_Outlet ;
 s223:hasMedium s223:Fluid-Air .

# Room 2 and its connection
ex:Room2 a s223:PhysicalSpace ;
 s223:encloses ex:Room2HVAC .

ex:Room2HVAC a s223:DomainSpace ;
 s223:hasDomain s223:Domain-HVAC ;
 s223:hasConnectionPoint ex:Room2_Inlet, ex:Room2_Outlet .

ex:Room2_Inlet a s223:InletConnectionPoint ;
 s223:isConnectionPointOf ex:Room2HVAC ;
 s223:cnx ex:Supply_Duct_Room2 ;
 s223:hasMedium s223:Fluid-Air .

ex:Room2_Outlet a s223:OutletConnectionPoint ;
 s223:isConnectionPointOf ex:Room2HVAC ;
 s223:cnx ex:Return_Duct2 ;
 s223:hasMedium s223:Fluid-Air .

# Supply Duct to Room 2
ex:Supply_Duct_Room2 a s223:Duct ;
 s223:hasMedium s223:Fluid-Air ;
 s223:cnx ex:VAV2_Outlet, ex:Room2_Inlet .

We are using an RDF representation of the 223P model, meaning we have decomposed the graph into triples of subject predicate object statements. This is significant, because it affects the kinds of traversals and queries we can perform on the model.

Deriving Views over RDF Graphs

Sun, 23 Feb 2025 00:00:00 +0000

(the model is in the eye of the beholder)

Part 2 of this post explores how we can define loops in a knowledge graph and how we can derive different views of the same loop for different applications.

Ontologies are a formal representation of a perspective on a domain. They are specific in what details they care about, and which details they don’t. This means that some ontologies are more appropriate for certain applications than others. Correspondingly, knowledge graphs using such an ontology may be better suited to answer certain questions over others. Some applications may require us to derive a new perspective on a particular knowledge graph. It is convenient to think of this derivation as a “view” or “projection” of the underlying knowledge graph which abstracts away the unnecessary detail for a particular application.

Brick Validation Example (with BuildingMOTIF)

Tue, 04 Feb 2025 00:00:00 +0000

We will use the Brick model from the previous post:

Expand for Brick Model

@prefix brick: <https://brickschema.org/schema/Brick#> .
@prefix rec: <http://w3id.org/rec/> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix unit: <http://qudt.org/vocab/unit/> .
@prefix : <urn:tutorial/> .

<urn:tutorial> a owl:Ontology ;
 owl:imports <https://brickschema.org/schema/1.4/Brick> ;
 owl:imports <http://qudt.org/2.1/vocab/unit> .

:building1 a rec:Building ;
 rdfs:label "Building 1" .

:floor1 a rec:Floor ;
 rdfs:label "Floor 1" .

:room1 a rec:Room ;
 rdfs:label "Room 1" ;
 rec:isPartOf :floor1 ;
 rec:isLocationOf :thermostat1 .

:thermostat1 a brick:Thermostat ;
 rdfs:label "Room 1 Thermostat" ;
 brick:hasPoint :room1-sp, :sensor1, :room1-occ .

:room1-sp a brick:Air_Temperature_Setpoint ;
 rdfs:label "Room 1 Setpoint" ;
 brick:hasUnit unit:DEG_F .

:sensor1 a brick:Air_Temperature_Sensor ;
 rdfs:label "Room 1 Temperature" ;
 brick:hasUnit unit:DEG_F .

:room1-occ a brick:Occupancy_Sensor ;
 rdfs:label "Room 1 Occupancy" .

We first set up the BuidlingMOTIF instance. The easiest thing to do here is create an in-memory instance so you can start fresh each time. Keep in mind that it can take a few seconds to load some of the larger ontologies, so for “real” projects you should consider using a persistent instance.

Minimal Brick Validation Example (no BuildingMOTIF)

Mon, 20 Jan 2025 00:00:00 +0000

This document provides a minimal example of how to validate a Brick model in Python without BuildingMOTIF. I would generally recommend using BuildingMOTIF for this purpose, but this example is useful for understanding the underlying processes.

Brick Model

A Brick model is a semantic model of a specific building. It is typically represented in the Turtle format. Here is an example of a simple Brick model:

@prefix brick: <https://brickschema.org/schema/Brick#> .
@prefix rec: <http://w3id.org/rec/> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix unit: <http://qudt.org/vocab/unit/> .
@prefix : <urn:tutorial/> .

<urn:tutorial> a owl:Ontology ;
 owl:imports <https://brickschema.org/schema/1.4/Brick> ;
 owl:imports <http://qudt.org/2.1/vocab/unit> .

:building1 a rec:Building ;
 rdfs:label "Building 1" .

:floor1 a rec:Floor ;
 rdfs:label "Floor 1" .

:room1 a rec:Room ;
 rdfs:label "Room 1" ;
 rec:isPartOf :floor1 ;
 rec:isLocationOf :thermostat1 .

:thermostat1 a brick:Thermostat ;
 rdfs:label "Room 1 Thermostat" ;
 brick:hasPoint :room1-sp, :sensor1, :room1-occ .

:room1-sp a brick:Air_Temperature_Setpoint ;
 rdfs:label "Room 1 Setpoint" ;
 brick:hasUnit unit:DEG_F .

:sensor1 a brick:Air_Temperature_Sensor ;
 rdfs:label "Room 1 Temperature" ;
 brick:hasUnit unit:DEG_F .

:room1-occ a brick:Occupancy_Sensor ;
 rdfs:label "Room 1 Occupancy" .

For the purpose of validation, the most important part is the 3 lines near the top declaring the ontology and its imports:

Present and Future of ASHRAE 223P (as of 2024/1/18)

Thu, 18 Jan 2024 00:00:00 +0000

I get enough questions about the current state of ASHRAE 223P https://www.ashrae.org/news/esociety/ashrae-bacnet-committee-works-with-other-organizations-on-new-standard that it was worth putting together a quick post collecting some of the slide decks, papers, and online resources that have emerged.

Open223

The current best resource for learning about 223P is the Open223 project. Open223 “is a collection of permissively-licensed open-source tools to facilitate exploration and usage of the emerging ASHRAE 223P standard. These tools are neither developed nor endorsed by ASHRAE – instead, they are maintained by a small community of enthusiasts and developers who believe in making RDF data easier to use.”

Point Mapping Overview

Wed, 21 Jun 2023 00:00:00 +0000

For additional background on Brick, be sure to check out the reading list

This document attempts a brief summary of “point mapping” techniques and technologies, with a particular emphasis on mapping point labels from a building management system (BMS) into a Brick model.

What are Point Labels?

BMS points are the I/O elements for a building For a good primer on BMS points see this article . They are the identifiers used by software to read data from the building (e.g. sensor values) and to write data to the building (e.g. changing setpoints). Points are given labels in the BMS – think of these like variable names used by software to perform the read/write actions. These labels are largely ad-hoc constructions driven by vendor- or site-specific conventions.

Shape to Query

Mon, 19 Jun 2023 17:54:57 -0600

SHACL Shape to SPARQL Query Transformation

SHACL shapes can be thought of as functions that take an RDF graph as an argument and return:

a boolean indicating if the shape was fulfilled on the graph, and
some extra metadata indicating why the shape was not fulfilled on the graph (if this is the case)

The SHACL validation is the process of evaluating the shapes on a given RDF graph. This checks the conditions associated with each shape and also adds any inferred information. The SHACL validation/inference process does not tell you how the shapes came to be fulfilled on the graph, only that they were.

Getting all template bodies from BuildingMOTIF

Mon, 12 Jun 2023 17:15:14 -0700

Here’s a quick how-to on load libraries into a BuildingMOTIF installation and then list all of the templates in those libraries as well as the bodies (RDF graph component) of those templates.

At this time (2023-06-13), BuildingMOTIF is still under active development so you’ll want to install it directly from GitHub You can also clone the repository directly and do this all within that environment :

pip install -e git+https://github.com/NREL/BuildingMOTIF#egg=buildingmotif

Now, create a file called libraries.yml which contains the following lines:

Resources for Incoming Graduate Students

Tue, 30 May 2023 00:00:00 +0000

Resources for Incoming Graduate Students

This page is an incomplete list of useful resources and tips for incoming graduate students at Colorado School of Mines. I’ve sourced these links from current graduate students at Mines, who know far better then me what resources were helpful to them! If there is anything missing or incorrect, please send me an email.

General Resources

Graduate Student Government page: a wonderful organization at Mines by graduate students for graduate students; links, resources, and contacts
CASA: student advising center; great for academic and scheduling support
Read the Daily Blast, the daily campus email, for events and resources
Get familiar with your degree requirements with additional specifics here; this will help you know what to expect, but be sure to regularly discuss degree progress with your advisor

Housing

Mines Park: nearby university-run apartment complex with amenities. Reduced availability for 2023-24 due to renovations, but an excellent option for students.
Off-campus housing facebook group; not affiliated with Mines; other groups are “Golden/arvada/denver roommates & housing” and “CSM housing, sublets & roommates”. Feel free to make an “In Search Of” post telling people what you are looking for
Look for Facebook, Craigslist or other groups online using keywords like “Golden housing” or “Denver housing”
Living near campus (in Golden) can be expensive, but there are plans for a future bus line connecting campus to the train station at the Jefferson County courthouse and South Golden road.

International Students

International Student Council: advocacy and support for international students; helps to coordinate international student organizations on campus; great place to find student clubs
[Housing] A few international students have indicated that Mines Park (above) is a popular housing location for many international students
Mines Graduate Student Government (GSG) has an equity/international student officer and an international student council representative; look on the GSG site above to find their contact information
There are a number of WeChat groups, Slack rooms, Discord servers, and other online social locations which have grown organically from students from certain countries and identities. Email the CS graduate student mailing list for specifics

Getting Started with Brick Research

Wed, 17 May 2023 00:00:00 +0000

This whole document is in-progress – be sure to check back!

Brick Research Reading List

So you want to do research on or with Brick – great! One common question I get or find myself answering is “what background do I need to get myself up to speed with using Brick at a level where I can do research?” This post attempts to answer that question.

For high-level background, please read through Chapter 2 of my PhD thesis – this is a decent overview of the information detailed below.

Brick Timeseries Data

Sun, 02 Feb 2020 17:15:14 -0700

Brick Timeseries Access

Here is a “completely” modeled zone air temperature sensor modeled in Brick

@prefix brick: <https://brickschema.org/schema/1.2/Brick#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix tag: <https://brickschema.org/schema/1.2/BrickTag#> .
@prefix : <urn:bldg#> .

:x a brick:Zone_Air_Temperature_Sensor ;
 brick:hasUnit unit:DEG_C ;
 rdfs:label "SODA1R410_ARS" ;
 # below, we will ignore the following properties as they
 # are orthogonal to the timeseries modeling discussion
 brick:isPointOf :hvac_zone_1 ;
 # automatically added
 brick:hasTag tag:Zone, tag:Air, tag:Temperature, tag:Sensor ;
.

How do we connect the temperature sensor x to a timeseries database? And what are the concerns we will need to handle?

Ontology Evaluation

Sun, 12 Jan 2020 17:14:12 -0700

This document establishes an empirical methodology for evaluating the 223 standard in order to codify the properties of 223 that make it successful and suitable for its intended use cases. We draw some inspiration from this paper, which established the empirical metadata evaluation methodology that drove development of the Brick ontology. The original Brick paper lays out three general properties of an ontology that make it successful for the building domain: completeness, extensibility and usability. We define each of these terms in the context of 223 and outline the specific evaluation procedures used.