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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Towards Digital Twin-based Operation and Maintenance: A Virtual Assistant Framework for Creating Guidelines According to Managers' Requirements</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Sheng Bao</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Hangdong Bu</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>College of Civil Engineering and Architecture, Zhejiang University</institution>
          ,
          <country country="CN">China</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Successful implementation of Digital Twin (DT) technology in Operation and Maintenance(O&amp;M) requires deep DT knowledge and extensive O&amp;M experience. To address this challenge, this paper introduces a virtual assistant framework named “DT-GPT” that utilizes Generative Pre-trained Transformer (GPT) to assist managers in creating DT-based O&amp;M guidelines according to their requirements. To determine managers' requirements, an O&amp;M requirements system with DT was developed. Based on the established requirements system, a three-step approach to employ DT-GPT was proposed to dynamically determine guidelines based on the project requirements and details. In a case study, DT-GPT's function is demonstrated through a virtual assistant prototype for campus management. The process exemplifies the potential of DT-GPT in facilitating the successful integration of DT in O&amp;M practices. This paper contributes to the advancement of efective and informed virtual assistants for DT in the O&amp;M stage, significantly reducing knowledge gaps, time, and cost for DT applications.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Digital Twin</kwd>
        <kwd>Operation and Maintenance</kwd>
        <kwd>Generative Pre-trained Transformer</kwd>
        <kwd>Virtual Assistant</kwd>
        <kwd>Large Language Model</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        With the integration of information technology (IT) across various industries, traditional sectors
have increasingly adopted IT to enhance eficiency and quality, particularly in the Architecture,
Engineering, and Construction (AEC) industry [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. A significant technological advancement in
this area is the concept of the Digital Twin (DT) [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], which integrates multi-disciplinary data to
support AEC activities, especially in Operation and Maintenance (O&amp;M) management [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. As
the longest stage in the building life cycle, O&amp;M increasingly relies on digital technologies to
manage complex building systems, including prediction, anomaly detection, and operational
optimization [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. This application can lead to substantial cost and time savings [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], risk reduction
[
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], and improved O&amp;M eficiency [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ].
      </p>
      <p>
        However, due to the novelty of DT in AEC industry, the application of DT and the construction
of Cyber-Physical System (CPS) for O&amp;M are still in the early stage. Current DT application
strategies and CPS development approaches require managers to possess extensive knowledge
and experience with DT, which is often lacking due to the scarcity of successful cases [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. To
address the challenges associated with DT applications, virtual assistants have been proposed
as a potential solution [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. Nevertheless, developing these virtual assistants presents significant
challenges, as it demands high levels of automation to accurately interpret diverse natural
language queries from various users [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
      <p>The rise of large language models (LLMs) brings new opportunities for DT applications
[11]. These models, pre-trained on extensive text corpora, have demonstrated remarkable
contextual learning capabilities in natural language processing (NLP) tasks via textual "prompts".
Among all LLMs, Generative Pre-trained Transformers (GPT) have shown powerful abilities
in generating and understanding natural language [12]. The core idea of the GPT model is
to leverage large-scale text corpora for unsupervised learning, gaining deep insights into the
structure and semantics of language. During the pre-training phase, the GPT model learns
statistical and language patterns from textual data. Subsequently, it enters a fine-tuning phase
tailored for distinct tasks like text generation, classification, and question answering [13].</p>
      <p>Based on the GPT-4 model, a virtual assistant is developed to assist managers in creating
guidelines during the planning stage. The major contributions of this study are as follows:
• A framework for an operation and maintenance requirements system with digital twins
has been developed to support the successful implementation of DTs in O&amp;M. This
proposed system includes model requirements, function requirements, and nongeometric
data requirements;
• A three-step approach to creating O&amp;M guidelines is presented. A novel aspect of our
approach is its dynamic determination of guidelines based on the project requirements
and details;
• This study utilizes the GPT-4 model to create the DT-GPT assistant, aiding managers
in formulating guidelines for digital operational management and identifying the
nongeometric data requirements of diferent projects. The guideline formulation process is
integrated with the proposed requirements system and three-step approach.</p>
      <p>The paper is organized as follows: Section 2 reviews the related literature. Section 3 presents
the framework for the operation and maintenance requirements system with digital twins.
Section 4 presents the three-step approach and the DT-GPT assistant. Section 5 describes a case
study on campus management. Finally, conclusions are drawn in Section 6.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Related Work on LLMs and DT-based O&amp;M</title>
      <p>In this section, we perform a comprehensive overview of related research on operation and
maintenance with digital twin technology. Meanwhile, we also review some assistants based on
GPT models and their applications in diferent fields.</p>
      <sec id="sec-2-1">
        <title>2.1. DT based O&amp;M</title>
        <p>
          The development of O&amp;M can be divided into three stages: the traditional stage which relies
on documents and personnel; the platform stage which requires a detection and management
platform, and the intelligence stage which integrates Building Information Modeling (BIM),
Artificial Intelligence (AI), Internet of Things (IoT) to assist decision-making [ 14]. Actually, the
intelligence stage aligns with the concept of Digital Twin proposed by Michael W. Grieves [15].
Current studies have proved the potential of implementing DT in O&amp;M management [16, 17, 18].
For example, a DT-based framework for automatically detecting and diagnosing faults in facilities
was built by Hosamo et al. [19]. Clausen [20] presented a DT framework to control heating
and ventilation by using data on weather forecasts, current- and planned occupancy as well as
the current state of the controlled environment. Francisco [21] established a DT platform for
urban-scale energy management and developed daily building energy benchmarks by leveraging
smart meter electricity data. Lombardo et al [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ] proposed a multi-layer DT-based architecture
aimed to enable the development of machine learning-based intelligent location based services.
The platform was evaluated in the complex scenario of healthcare organization, achieving high
accuracy and eficiency.
        </p>
        <p>
          Although the necessity of DT in O&amp;M has been recognized since 2010 [22], managers have not
fully embraced its benefits [ 23]. A main barrier is the challenge of how to employ DT to support
management, considering the requirements of managers [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ]. To address the issue, Cavka et
al. [24] investigated six projects to map the relationship between organizational constructs,
owner requirements, and model. It helps owners understand how to approach the handover of
digital facility models and determine their model requirements based on specific needs. Chen et
al. [25] identified the information requirement and proposed a ontology-based framework for
facility maintenance management. A data structure for O&amp;M data requirements was developed
by Becerik-Gerber [26] to support successful implementations of DT in O&amp;M.
        </p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. LLMs Assistant and Applications in O&amp;M</title>
        <p>LLMs are a sophisticated category of Machine Learning (ML) models crafted to comprehend
and generate human-like language. They achieve this capability through extensive pre-training
on large amounts of text data [27, 28]. Preview studies have explored LLMs assistants and their
applications in DT-based O&amp;M. Shamshiri [29] reviewed publications related to text mining
and NLP in architectural management, discovering that leveraging pre-trained language models
presents a potential research opportunity. Lu [30] evaluated LLMs on the mastery of knowledge
and skills in the heating, ventilation, and air conditioning (HVAC) system. Results showed
that GPT-4 can pass the ASHRAE Certified HVAC Designer examination with scores from 74
to 78, which is higher than about half of human examinees. Based on GPT-4, an automated
data mining framework for building energy conservation was proposed by Zhang [12]. The
detection accuracy of GPT is 89.17% for energy waste patterns and 99.48% for normal operation
patterns. The response time and cost of GPT are 6747.60s and $17.68, respectively.</p>
        <p>In addressing the DT model issue, Jang [31] proposed Natural-language-based Architectural
Detailing through Interaction with AI (NADIA). Instead of using menu-based user interfaces,
NADIA enables model design detailing using natural language. The validation results showed
an average accuracy of 83.33% in generating logically coherent details and 98.54% in complying
with ASHRAE standard. A virtual assistant named BIMS-GPT was presented by Zheng et
al. [32] to search for information from models eficiently. When evaluated with a BIM query
dataset, this assistant achieves a 99.5% accuracy rate in classifying natural language queries
while incorporating only 2% of the data in prompts.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. Research Gaps</title>
        <p>Based on the above review of DT-based O&amp;M and LLMs assistants, three principal research
gaps in previous studies are summarized:
• Although certain studies have investigated the requirements of managers to successfully
implement DT in O&amp;M, their established requirements systems are confined to specific
aspects such as modeling or data;
• While applying these digital technologies requires professional knowledge, there is limited
research focused on assisting managers in creating guidelines to ensure their efective
utilization;
• To the best of the authors’ knowledge, there is currently no research available on the
utilization of LLMs to assist managers in leveraging DT technology for implementation
based on their requirements.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Operation and Maintenance Requirements System with</title>
    </sec>
    <sec id="sec-4">
      <title>Digital Twins</title>
      <p>As explained in the previous section, the advantages of implementing DTs in O&amp;M stage can be
significant. However, due to the novelty of technology, many managers have knowledge gaps
in planning, arranging, and applying DTs in O&amp;M stage. We investigated three projects that
implemented DT technology during the O&amp;M stage in China. Documents such as standards,
guidelines and models were collected and analyzed [24]. Furthermore, we conducted interviews
with owners, facility managers and O&amp;M personnel, and followed workers to observe their
daily workflows. Three main barriers are concluded as follows:
• There is a lack of modeling standards oriented towards operation and maintenance
management, including level of details, component coding and naming rules, model
decomposition rules, model color classification rules, and data exchange standards;
• The concept of digital twins and their potential value are not suficiently understood by
managers. They lack clarity on how DTs can integrate with existing O&amp;M processes and
the specific functions DTs can ofer to improve management and deliver benefits;
• While accurate as-built models containing geometric data serve as the “cyber” part of the
CPS, there exist unclear requirements in nongeometric data gathered by IoT from the
“physical” part.</p>
      <p>This paper presents the Operation and Maintenance Requirements System with Digital Twins
that aims to support successful implementation of DTs in O&amp;M. As depicted in Figure 1, the</p>
      <p>Model
Requirements</p>
      <p>Function
Requirements
Nongeometric</p>
      <p>Data
Requirements
Decomposition Rules</p>
      <p>Color Classification Rules</p>
      <p>Data Exchange Standards
Facility</p>
      <p>O&amp;M
Human</p>
      <p>Environment</p>
      <p>Management</p>
      <p>Facility
Security</p>
      <p>Asset
Environment</p>
      <p>Space
Emergency</p>
      <p>Energy
Personnel
Asset Details</p>
      <p>Operational History</p>
      <p>Real-Time Metrics
proposed requirements system comprises three primary parts: model requirements, function
requirements, and nongeometric data requirements.</p>
      <sec id="sec-4-1">
        <title>3.1. Model Requirements</title>
        <p>As illustrated in Table 1, model requirements encompass five key aspects to better serve the
O&amp;M stage. Level of detail (LOD) describes the precision of components in terms of geometric
shape, size, position, and other attributes within the model. Typically, LOD is categorized into
diferent levels, ranging from lower levels (e.g., LOD 100), which represent the basic shape of
components in the model, to higher levels (e.g., LOD 500), which signify detailed geometric
shape, size, material, and other attributes of components. The appropriate LOD should be
determined based on the specific project requirements and objectives, rather than striving for
the highest possible level.</p>
        <p>Given the multi-participation of projects, it is essential to establish standardized component
coding and naming rules to improve the delivery and retrieval of models. UniFormat [35] and
OmniClass [36] are commonly utilized standards to identify various types of components by
shortcode.</p>
        <p>Considering that models for large-scale projects involve a great amount of information and
data, model decomposition rules should be established to divide the model into smaller parts
to facilitate management and operation. Typically, architectural and structural models are
decomposed based on usage and space, while MEP (Mechanical, Electrical, Plumbing) models
are decomposed according to disciplines, systems, and subsystems. Due to the complexity
of MEP models, model color classification rules should also be established to display models
intuitively. Diferent systems within the model can be distinguished by varying colors and fill
patterns. Table 1 presents some examples of color classification rules.</p>
        <p>Although models can serve as carriers of data, providing support for management decisions
through integrated data, the data must conform to specific standards. This conformance helps to
avoid issues such as inconsistent data formats or information loss and facilitates easier exchange
and sharing of data among diferent software and systems. Currently, the Industry Foundation
Classes (IFC) [37] and Construction Operations Building information exchange (COBie) [38]
standards are internationally utilized for this purpose.</p>
      </sec>
      <sec id="sec-4-2">
        <title>3.2. Function Requirements</title>
        <p>As a new concept, DT is not widely known by managers. DTs involve technologies from multiple
ifelds, including IoT, big data, AI, BIM, etc. These technologies can be too complex for managers
with non-technical backgrounds to understand their implementation and application. Moreover,
although DTs have been applied in some fields, successful cases in O&amp;M are relatively scarce.
Managers lack the experience necessary to evaluate the potential and benefits of DTs in O&amp;M.</p>
        <p>To address these challenges, function requirements are proposed to assist managers in
understanding the capabilities of DTs in O&amp;M. This can encourage managers to apply DTs more
actively, thereby enhancing the level and eficiency of management. Table 2 lists the function
requirements from eight aspects of management, which were established by literature analysis,
on-site survey, and interviews. Based on these function requirements, managers can develop
digital twin implementation plans aligned with their management objectives.</p>
      </sec>
      <sec id="sec-4-3">
        <title>3.3. Nongeometric Data Requirements</title>
        <p>Data requirements can be divided into geometric data requirements and nongeometric data
requirements. Notably, geometric data requirements, such as BIM data, consist of dimensions,
shapes, and spatial locations of buildings or equipment. Since geometric data is typically
integrated into the model, we categorize it under model requirements as mentioned in Section
3.1.</p>
        <p>There is an increasing need to identify nongeometric data requirements to support successful
implementation of DTs in O&amp;M [54, 55, 56]. To meet this need, we have established a framework
for nongeometric data requirements in Figure 2.</p>
        <p>Asset details refer to the static details of components, such as names, locations, materials,
models, installation dates, and technical specifications. These data should ideally be gathered at
the beginning of a project, with sources including the construction contractors and equipment
manufacturers. Once established, asset details remain constant and can be integrated into the
components of a model along with geometric data.</p>
        <p>Operational history denotes the record-based data of equipment, encompassing activities
such as switch adjustments, operational state modifications, fault alerts, and similar logging
activities. By analyzing the operational history of equipment, the operational patterns, fault
frequencies, and characteristics of the equipment can be identified, thereby formulating efective
maintenance schedules. Utilizing data analysis based on historical working records enables the
prediction of potential equipment failure times, facilitating the implementation of preventative
maintenance measures to mitigate downtime and maintenance costs.</p>
        <p>Real-time metrics refer to the various indicators or parameters that characterize the state of
equipment during its operation. These data are utilized for monitoring the performance, health
status, and operational conditions of the equipment. Real-time metrics are gathered by installing
various sensors on the physical equipment, such as temperature sensors, pressure sensors,
vibration sensors, flow sensors, etc., selected based on the characteristics of the equipment and
function requirements.</p>
        <p>The volume of data increases significantly from top to bottom. Nongeometric data
requirements must be discerned and captured through a workflow at diferent stages of a project.
Becerik-Gerber et al have listed the continuum stakeholders responsible for data provision [26].
Identifying and gathering the necessary nongeometric data demands a visionary leader who
is capable of guiding the entire process. Additionally, forming a Digital Twin team consisting
of stakeholders is important to delineate the responsibilities for providing relevant data at
each stage. Lastly, supervisory mechanisms should be established to ensure the suficiency and
quality of the collected nongeometric data.
Environment management [52]</p>
        <p>Personnel management [53]</p>
        <p>Real-time monitoring</p>
        <p>Remote control
Routine maintenance
Predictive maintenance</p>
        <p>Space planning</p>
        <p>Space occupancy
Behavior monitoring</p>
        <p>Digital patrolling</p>
        <p>Smart Parking</p>
        <p>Fire monitoring
Evacuation planning</p>
        <p>Asset database</p>
        <p>Asset tracking
Consumption monitoring
Operation optimization
Environment monitoring
Operation optimization</p>
        <p>Personnel database
Visitor Appointment</p>
        <sec id="sec-4-3-1">
          <title>Description</title>
          <p>Real-time monitoring of the status of
equipment or systems, with alarms triggered in
case of malfunctions or anomalies.
Remote control of equipment or system
status through a platform or mobile
application.</p>
          <p>In case of faults, maintenance work orders
can be promptly dispatched to maintenance
personnel.</p>
          <p>Utilizing simulation and machine learning
to forecast potential faults.</p>
          <p>Planning room size and interior spatial
layouts. Allocating rooms to users that meet
their needs.</p>
          <p>Analyzing space occupancy and vacancy
rates.</p>
          <p>Issuing alarms for behaviors such as
unauthorized entry, theft, and falls.</p>
          <p>Planning patrol routes and schedules.
Issuing alarms for anomalies.</p>
          <p>Integrating recognition, positioning,
tracking, monitoring, and management into
smart parking systems.</p>
          <p>Monitoring the status of sensors. Issuing
alarms and notifications upon detecting a
fire.</p>
          <p>Planning evacuation routes in the model
based on monitoring of corridors, stairs, and
emergency exits.</p>
          <p>Recording asset entry, exit, inventory, and
depreciation to manage assets more
eficiently.</p>
          <p>By integrating RFID tags with the model,
assets can be swiftly located and tracked.
Monitoring energy consumption data and
setting up energy consumption plans by
zone.</p>
          <p>Integrating models and energy
consumption data for stimulating and forecasting
energy consumption.</p>
          <p>Optimizing equipment operation strategies
based on energy consumption forecasts to
minimize energy usage and costs.</p>
          <p>Monitoring the environment and issuing
alarms when indicators exceed predefined
limits.</p>
          <p>Optimizing lighting and HVAC systems’
operation strategies based on environmental
monitoring results.</p>
          <p>Establishing a personnel database to record
daily attendance information.</p>
          <p>Supporting online submission of visitor
appointment requests and maintaining a
record of historical data.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>4. LLMs-based Assistant</title>
      <p>The overall framework of proposed DT-GPT Assistant, which is based on the operation and
maintenance requirements system in Section 3, is depicted in Figure 3. DT-GPT Assistant can
assist managers in creating guidelines for digital operational management and identifying the
nongeometric data requirements of diferent projects. It comprises three main modules: the
function module, the component module, and the data module. Every module was developed
based on the GPT-4 model, enabling interaction through natural language.</p>
      <sec id="sec-5-1">
        <title>4.1. Function Module</title>
        <p>The function module is designed to meet function requirements, assisting managers in
establishing the goals that a project needs to achieve during O&amp;M management at planning stage. It
facilitates subsequent workflows such as building models and deploying CPS. Considering
various O&amp;M management requirements, the function module proposes three versions of function
lists: Basic, Advanced, and Intelligent versions.</p>
        <p>Basic Version includes fundamental functions such as routine maintenance schedules,
equipment monitoring, energy management, and safety inspections. It caters to managers requiring
essential maintenance and monitoring to ensure operational eficiency and compliance with
safety standards.</p>
        <p>Advanced Version is built upon the Basic Version by incorporating system interconnectivity
and O&amp;M management data analysis. It is designed for managers seeking to enhance
operational insights and eficiencies through more sophisticated data-driven strategies and system
integration, facilitating proactive maintenance and optimization.</p>
        <p>Intelligent Version elevates the Advanced Version by integrating intelligent functions powered
by artificial intelligence algorithms. It is dedicated to assisting forward-thinking managers in
User</p>
        <p>Basic Version
Advanced Version
Intelligent Version</p>
        <p>DT-GPT Assistant
utilizing AI for predictive maintenance, energy optimization, and advanced security solutions,
thereby achieving the highest level of eficiency, sustainability, and occupant comfort.</p>
      </sec>
      <sec id="sec-5-2">
        <title>4.2. Component Module</title>
        <p>Considering the variability of each project and ensuring the completeness of the component list,
we have developed the component module to extract components directly from design drawings.
This module can read design drawings of various disciplines. Each component is extracted and
its relevance to O&amp;M process is identified using the GPT-4 model. Finally, component lists for
various disciplines are generated.</p>
        <p>The component module ensures that all components in the design are accounted for and
aids the O&amp;M teams in better comprehending the system’s structure and composition. This
understanding is crucial for developing appropriate maintenance management strategies and
procedures. Additionally, by generating these component lists, managers can determine the
data needed to be collected during diferent project stages.</p>
      </sec>
      <sec id="sec-5-3">
        <title>4.3. Data Module</title>
        <p>Based on the nongeometric data requirements mentioned in section 3, the data module is
designed to provide the asset details, operational history, and real-time metrics of components
extracted by the component module. Components capable of interfacing with the CPS via IoT
technology include all three types of non-geometric data: asset details, operational history, and
real-time metrics. Conversely, components unable to access the CPS through IoT technology
have non-geometric data that include only asset details and operational history. By leveraging
the data module, managers can specify the necessary data according to the attributes and
operational requirements of diferent components. This structured approach optimizes the
data collection process, ensuring that the collected data matches subsequent analysis and
management needs. Additionally, managers can selectively gather essential data instead of
conducting indiscriminate large-scale data collection, thus conserving resources and reducing
costs.</p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>5. Case Study: LLMs-based Digital Twins in Campus</title>
    </sec>
    <sec id="sec-7">
      <title>Management</title>
      <p>To validate the feasibility of the proposed O&amp;M requirements system and the DT-GPT assistant,
we applied them in the project of the International School of Medicine, Zhejiang University
(ISMZJU). ISM-ZJU started construction in 2020, leveraging a diverse array of technologies including
cloud computing, big data, IoT, AI, and DTs. These technologies facilitated the integration
of data from individuals, spaces, and equipment within the campus, thereby enhancing the
digitization and intelligence of campus management.</p>
      <p>Natural Language Queries</p>
      <p>Function Module</p>
      <p>Function List
Lighting System
HVAC System
Power System
Entrance System
…</p>
      <p>Filter
Final Function List</p>
      <p>Design Drawings
Component Module
Components List</p>
      <p>Light Fixture</p>
      <p>Air Filter
Energy Meter
Fire Sprinkler
…</p>
      <p>Filter According to</p>
      <p>Final Function List
Final Components List
t
c
a
r
t
x
E</p>
      <p>Names of Components</p>
      <p>Data Module
Nongeometric Data List</p>
      <p>Asset Details
Operational History
Real-Time Metrics</p>
      <p>Filter</p>
      <p>Final Nongeometric Data List</p>
      <p>Guideline for DTs-based Operation and Maintenance Management</p>
      <p>Figure 4 presents the process of employing DT-GPT in ISM-ZJU. At the project’s outset,
managers opted to integrate DT technology into the O&amp;M stage. The function module of
DT-GPT assistant was employed to generate function lists according to natural language queries
inputted by managers. Function lists involved functions of various systems that the CPS could
achieve. Managers filtered these functions based on their management objectives. Consequently,
the final function list was made.
Electrical Design Drawings</p>
      <p>Plumbing Design Drawings
DT-GPT
Display diferent operational states of equipment through colors and
animations.</p>
      <p>Establish an interface displaying schematic diagrams of the electrical
distribution system.</p>
      <p>Filter and display equipment models based on profession, system,
floor, space, status, and other conditions.</p>
      <p>Click on the equipment model to display the ledger.</p>
      <p>Real-time display of equipment operating parameters within the
model.</p>
      <p>Organize equipment operation and maintenance records by year,
month, day, and other time intervals.</p>
      <p>Attach QR codes to equipment surfaces. Scanning the QR code with a
mobile device will automatically link to the relevant equipment data.</p>
      <p>Alarm and log abnormalities in the distribution transformer system.</p>
      <p>Automatically send alarm events to management personnel via SMS,
app notifications, etc.</p>
      <p>Generate work orders automatically when alarms occur and provide
the option to send the work orders through selection.</p>
      <p>The alarm data can be categorized and summarized by system, alarm
type, location, etc., and can be exported in Excel format.</p>
      <p>The model displays camera locations in the electrical distribution area.</p>
      <p>Clicking on a camera allows to view the video surveillance feed.</p>
      <p>Subsequently, the component module of DT-GPT assistant was utilized to extract components
relevant to O&amp;M from various design drawings. Managers filtered components based on the
ifnal function list and their management objectives, thus identifying the final component list.</p>
      <p>Following this, names of components in the final component list were inputted into the
data module of DT-GPT assistant. As a result, asset details, operational history, and real-time
metrics of each extracted component were provided. Considering management requirements
and costs of arranging sensors, managers filtered nongeometric data and determined the final
nongeometric data list. Finally, three lists were organized to form a DT-based campus O&amp;M
guideline.</p>
      <p>Figure 5 illustrates the specific inputs and outputs of DT-GPT. For the function module,
examples of natural language queries are as follows: 1) Provide me with a basic/advanced/intelligent
version of the operation and maintenance function list. 2) Can you add some intelligent
functions to the function list that you have generated? 3) Create a basic operation and maintenance
function list for me that covers the lighting system, HVAC system, etc. Table 3 presents the
results of electrical distribution system generated by DT-GPT.</p>
      <p>The component module read mechanical, electrical, and plumbing design drawings.
Components in drawings were extracted. The module traversed all components and assessed their
relevance to the O&amp;M process. Consequently, the components list was generated. Table 4
presents a partial list of mechanical, electrical, and plumbing components extracted using the
component module in ISM-ZJU.</p>
      <p>Water collector, radiator, manual air vent valve, water filter, pressure gauge,
electric air damper, outdoor unit, fresh air handling unit, kitchen exhaust unit,
thermostat, fan coil unit, horizontal centrifugal pump, submersible pump.</p>
      <p>Single-tube LED lamp, double-tube LED lamp, standard ceiling light,
threehole concealed safe socket, fire emergency lighting fixture, single/double
two-way switch, power distribution box.</p>
      <p>Drain funnel, pressure reducing orifice plate, Y-type strainer, gate valve, angle
valve, outdoor fire hydrant, hot water return pipe, fire hydrant water supply
pipe, domestic wastewater pipe, domestic wastewater pipe, siphonic rainwater
hopper.</p>
      <p>Names of components in the components list were inputted into data module. The module
traversed every name and generated their asset details, operational history, and real-time
metrics. Besides, managers could request the data module to add or adjust nongeometric data if
they were not satisfied. Table 5 presents a partial nongeometric data list generated by the data
module in ISM-ZJU.</p>
      <p>Since the DT-GPT assistant always ofers more information than necessary for actual O&amp;M
needs, a DT team involving members of diferent disciplines was built to help managers filter
functions, components, and data. In addition, this team plays a role in facilitating the
implementation of DTs, such as verifying data collection situation and inspecting the completion of
Name, production date,
manufacturer and contact
information, product
model, installation date
and location, rated voltage,
rated current, rated power,
connection group label,
cooling method,
shortcircuit impedance, weight.</p>
      <p>Name, production date,
manufacturer and contact
information, product
model, installation date
and location, execution
standard, license number,
weight, rated voltage,
rated current, rated power,
diameter, flow rate, head.</p>
      <p>Name, production date,
manufacturer and contact
information, product
model, installation date
and location, dimensions,
interface dimensions,
airflow, static pressure,
power, wind speed, noise,
eficiency, weight.</p>
      <p>Name, production date,
manufacturer and contact
information, product
model, installation date
and location, execution
standard, diameter, depth,
core material.</p>
      <sec id="sec-7-1">
        <title>Working Records</title>
      </sec>
      <sec id="sec-7-2">
        <title>Operational Parameters</title>
        <p>State adjustment, mainte- Communication status,
nance and service records, start/stop, power factor,
alarm records (fault, over- voltage, current, power,
load, high temperature, temperature.
voltage abnormality,
current abnormality).</p>
        <p>State adjustment, mainte- Communication status,
nance and service records, start/stop, flow rate,
presalarm records (fault, motor sure, manual/automatic
fault, overload, high tem- mode, rotation speed,
perature, low water level, power.
high pressure).</p>
        <p>State adjustment, mainte- Communication status,
nance and service records, start/stop, flow rate,
presalarm records (fault, abnor- sure, manual/automatic
mal wind speed, abnormal mode, power, temperature,
temperature and humidity, humidity, pressure, wind
abnormal pressure, abnor- speed, flow rate.
mal flow rate).
maintenance records,
replacement records.</p>
        <p>None.
the CPS. Figure 6 presents the interface of the CPS for the project. Figure 7 shows the interfaces
of mobile applications for workers and residents. As of now, a total of 13 subsystems and 9638
equipment have been integrated into the system.</p>
      </sec>
    </sec>
    <sec id="sec-8">
      <title>6. Conclusions and Future Work</title>
      <p>This paper introduces DT-GPT, a virtual assistant framework for creating DT-based O&amp;M
guidelines according to managers’ requirements. To determine the requirements of managers,
operation and maintenance requirements system with digital twins is established, including
model requirements, function requirements, and nongeometric data requirements. The
framework of DT-GPT consists of three major parts: function module, component module, and data
module. Combining DT-GPT, a three-step approach is proposed for dynamically determining
guidelines based on the project requirements and details. The implementation of this framework
is demonstrated through a virtual assistant prototype developed for ISM-ZJU, serving as a
case study. The results illustrate that the prototype eficiently assists managers in supporting
successful implementation of DT in O&amp;M.</p>
      <p>Although the results of our framework appear promising, several limitations need to be
acknowledged. The current framework of DT-GPT requires evaluation using objective metrics,
such as accuracy in generating guidelines. Additionally, the DT-GPT deployment process still
needs managers to filter information according to their management objectives. Future work
can focus on improving the automation level in guideline generation. Finally, since the case
study was focused on the application of campus management, future research could explore its
adaptation and optimization for various project types.</p>
      <p>In conclusion, DT-GPT represents a significant advancement in the field of virtual assistant
frameworks for DT in O&amp;M, ofering practical solutions to bridge the gap between technology
and management requirements. By facilitating the seamless integration of DT into operational
practices, this framework holds promise for driving innovation, improving decision-making,
and maximizing eficiency in a wide range of industries.
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