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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>v. 1 of ESP Journal of
Engineering &amp; Technology Advancements</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.56472/25832646/JETA-V1I2P123</article-id>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Kharkiv National University of Radio Electronics</institution>
          ,
          <addr-line>Nauky Ave. 14, Kharkiv, 61166</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Lviv Polytechnic National University</institution>
          ,
          <addr-line>Stepan Bandera street 12, Lviv, 79013</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2021</year>
      </pub-date>
      <volume>1</volume>
      <fpage>0000</fpage>
      <lpage>0001</lpage>
      <abstract>
        <p>While existing Holistic Adaptive Optimization Techniques (HAOT) in distributed data streaming systems excel at parameter tuning, they are insufficient for identifying latent vulnerabilities that can lead to future pipeline failures. To address this gap, this paper introduces a novel framework for Adaptive Issue Detection integrated within the HAOT architecture. The core of this framework is a novel Competency Module that enhances pipeline intelligence through two synergistic components: a Machine Learning (ML) Model for Issue Detection and an interactive Control Center. The ML model employs a range of algorithms, including anomaly detection and reinforcement learning, to incrementally analyze historical and real-time pipeline data. It proactively identifies issues such as the Small Files Problem, Data Skew, Resource Exhaustion, Throughput Degradation, and Latency Spikes. Complementing the ML model is the Control Center, a web-based interface that translates the model's complex analytics into clear, data-driven recommendations and risk assessments. Through intuitive charts and alerts, it provides operators with a centralized view of pipeline health, identified risks, and clear, datadriven recommendations. This human-in-the-loop system not only facilitates informed decision-making but also allows user feedback to guide the optimization process. By creating a symbiotic feedback loop between automated ML discovery and human operational expertise, our framework provides a robust, adaptive solution for enhancing the performance, efficiency, and reliability of distributed data streaming systems.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        The history of data processing architecture is marked by a series of advancements, each designed to
overcome the shortcomings of the previous generation. Initially, the Extract-Transform-Load (ETL)
framework was the standard. This process (Fig. 1) involved pulling raw data from on-premises,
transforming it using constrained storage and computational power, and finally depositing the
refined data into a centralized data warehouse. While a functional solution for its time, this
traditional ETL method had notable weaknesses, including limited processing power and scalability,
which made it challenging to manage and analyze growing volumes of historical data efficiently [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
      </p>
      <p>
        The second generation of data architecture, centered on the Extract-Load-Transform (ELT) model,
was a direct response to earlier limitations. ELT prioritizes speed by first loading raw data into a
scalable cloud Data Lake before transforming it with powerful, parallel computing resources. This
approach, often using a medallion framework, delivers high performance and supports advanced
analytics for downstream applications (as depicted in the ETL vs. ELT diagram in Fig. 2) [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
      </p>
      <p>
        However, this ELT model is not without its flaws. Its batch-based nature can create data delays
and inconsistencies. A more significant issue is operational inefficiency, where different teams (e.g.,
AI, Marketing) build redundant data pipelines for their specific needs. This practice, often
undocumented, leads to wasted resources, increased costs, and maintenance difficulties. The addition
of Reverse ETL processes further exacerbates these problems by creating additional copies of data
and increasing processing overhead [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ].
      </p>
      <p>In today's competitive business world, data is a critical asset, and organizations need immediate
access to reliable, contextualized data to foster innovation and thoughtful decision-making. The
"Shift-Left Architecture" has been introduced as a solution to meet these demands.</p>
      <p>
        Inspired by "Shift-Left Testing" in software development, this architecture moves data processing
and governance closer to the origin of the data. It emphasizes processing data in real-time as it is
generated, utilizing tools such as Apache Kafka and Apache Flink. This approach focuses on creating
reliable "data products" at the source for systems like Snowflake or Databricks. Following a "build
once, use many times" principle, this method ensures data is prepared efficiently for widespread
reuse, which reduces redundancy and boosts data quality throughout the company [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ].
      </p>
      <p>
        As illustrated in Figure 3, the Shift-Left Architecture redesigns data workflows by performing
tasks like cleaning and enrichment early. This ensures that all downstream systems, from analytics
platforms to operational microservices, receive high-quality, structured data, thereby minimizing
repetitive work and reducing the time required to gain valuable insights [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ].
      </p>
      <p>
        One of the most significant aspects of the Shift-Left approach is its strong alignment with the
principles of a data mesh, which it facilitates by creating real-time data products. This architecture
utilizes a combination of technologies, including Apache Kafka, Apache Flink, and Apache Iceberg,
to unify both operational (transactional) and historical (analytical) data processing. The result is a
consistent and reliable stream of high-quality data that can be processed instantly or loaded into
advanced analytics platforms, such as Snowflake, Databricks, or Google BigQuery. This creates a
solid, cohesive foundation for an organization's artificial intelligence and data analytics
initiatives [
        <xref ref-type="bibr" rid="ref4 ref5">4, 5</xref>
        ].
      </p>
      <p>
        Recent research on the Shift-Left Architecture has revealed the importance of integrating
earlystage anomaly detection and risk mitigation protocols. This approach will focus on identifying and
resolving data integrity issues — including quality, schema, and security defects — at the source,
thereby preventing their downstream escalation and minimizing costly operational rework. A
specialized Competency Module was suggested within the architecture to facilitate this, providing
data engineers with the necessary tools and expertise for proactive issue resolution. The early issue
detection significantly enhances the overall resilience and operational effectiveness of the data
architecture [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ].
      </p>
      <p>In this article, we design and evaluate a framework for adaptive issue detection within streaming
systems.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Related Works</title>
      <sec id="sec-2-1">
        <title>2.1. Limitations of Traditional ETL and ELT Paradigms</title>
        <p>A central challenge in data engineering is efficiently and reliably processing vast, real-time data
streams. Foundational methodologies such as Extract-Transform-Load (ETL) and
Extract-LoadTransform (ELT) have been extensively analyzed. However, their architectural limitations present
significant obstacles for industries that require low-latency and high-fidelity data. This review
examines the evolution of these paradigms, focusing on their inherent issues and the subsequent
attempts to resolve them.</p>
        <p>Initially, the ETL paradigm became the standard for data warehousing. However, as Nishanth
Reddy Mandala notes in his research, “ETL in Data Lakes vs. Data Warehouses” [7], its design suffers
from inherent issues. The required pre-load transformation step causes significant delays,
postponing data availability. Additionally, its rigid, schema-on-write approach reduces flexibility. It
also results in high costs for maintenance and scaling, making it less suitable for the evolving needs
of Big Data environments.</p>
        <p>To counteract ETL's limitations, the ELT approach was introduced, which delays transformation
until after the data is loaded — a core concept of the Lakehouse paradigm described by Gupta and
Yip in their book, “Delta Lake - Deep Dive” [8]. While this resolves the initial latency issue, the
multihop architecture of ELT creates its own significant challenges. Data freshness is impacted by delayed
updates, as longer pipelines slow refresh cycles. Development becomes less efficient, with increased
time-to-market and duplicated processing tasks across different business units [9]. This redundancy
also raises costs, as computationally intensive transformations are repeated multiple times. Most
importantly, this fragmented approach often leads to inconsistent data across operational and
analytical systems, preventing a unified, real-time view.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. The Emergence of the "Shift-Left" Architecture</title>
        <p>In response to these ongoing challenges, new paradigms have been introduced, such as the one
described in the article “Shift Left: Headless Data Architecture” [10] and the unified approach
explored in “An Overview of Shift Left Architecture” [11]. This "Shift-Left" approach fundamentally
alters the data pipeline by moving processing closer to the data source. Its primary goal is to address
the issues inherent in traditional models by enhancing processing efficiency, facilitating real-time
data handling, and consolidating workloads. A key benefit is the potential for improved data quality,
as it enables early detection and correction of issues, preventing their spread downstream.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. The Critical Challenge of "Bad Data" in Streaming Architectures</title>
        <p>However, as Adam Bellemare critically observes in his work, “Shift Left. Unifying Operations and
Analytics With Data Products,” this architecture's design introduces a major vulnerability: the
detection and management of "bad data" [12]. The reliance on immutable, append-only data streams
means that corrupted data, once introduced, cannot be easily changed or removed. Unlike traditional
ETL/ELT pipelines that can "stop the world" to make corrections, a faulty record in a streaming
architecture can cascade downstream, leading to severe and potentially irreversible business impacts.
Bellemare highlights key limitations, including the high cost of data reconciliation and the fact that
downstream consumers bear the burden of ensuring data consistency without owning the source
system.</p>
        <p>While Bellemare proposes reactive strategies—such as robust validation ("Prevention"), corrective
notifications ("Issue Correction Events"), and stream recreation ("Rewind, Rebuild, and Retry") —
these methods mainly deal with errors after they happen. This creates a significant gap: the absence
of a proactive approach to foresee and prevent issues before they impact performance or lead to data
loss. The Shift-Left architecture remains very vulnerable to early errors caused by incorrect data
schemas, flawed processing configurations, or sudden workload changes [13].</p>
        <p>To create an effective monitoring solution, it is essential to first gain a deep and detailed
understanding of the problem domain. Distributed data streaming systems, while powerful, present
a unique set of operational challenges that distinguish them from traditional monolithic or
batchbased systems.</p>
      </sec>
      <sec id="sec-2-4">
        <title>2.4. Analysis Issues in Distributed Data Streaming Systems</title>
        <p>The subsequent studies, “Demeter: Resource-Efficient Distributed Stream Processing under Dynamic
Loads with Multi-Configuration Optimization” [14] and “Towards Fine-Grained Scalability for
Stateful Stream Processing Systems” [15], explored key challenges in streaming, including resource
exhaustion, throughput decline, and latency spikes. They observed that uncontrolled resource use —
driven by data surges or stateful operations, such as windowed aggregations — can cause
backpressure, node failures, or reduced service quality. Excessive uploads can deplete compute and
storage resources, resulting in increased costs or service outages. Solutions such as horizontal scaling
and dynamic configuration (e.g., Demeter) help optimize resource use during fluctuating loads.</p>
        <p>The studies also addressed throughput issues, which occur when high data volumes overwhelm
network bandwidth and hardware, resulting in congestion, packet loss, and processing delays. For
instance, overloaded Kafka shards or Flink operators increase acknowledgment times, delaying
realtime dashboards. To counter these problems, techniques such as compression (Avro/Protobuf), load
balancing, and adaptive bitrate encoding are recommended to sustain throughput during traffic
surges.</p>
        <p>Lastly, structural bottlenecks — such as synchronous replication in geo-distributed systems or
network congestion during peak periods — can cause delays exceeding 50 seconds in live streaming.
Mitigation strategies include edge caching, asynchronous replication, and traffic-shaping protocols.</p>
      </sec>
      <sec id="sec-2-5">
        <title>2.5. Analysis of Performance Bottleneck</title>
        <p>The work “A Deep Dive into the Latest Performance Improvements of Stateful Pipelines in Apache
Spark Structured Streaming” [16] examines performance bottlenecks in streaming data pipelines. A
bottleneck is a component or resource that limits overall throughput or increases a system's latency,
acting as a choke point in the data flow. The key performance metrics, latency (the processing delay)
and bandwidth (the processing rate), are directly affected by the following constraints:
 Network bottlenecks occur when there is insufficient bandwidth to handle traffic, high
latency caused by physical distance or congestion, or an inefficient network layout with
excessive hops. For example, a video streaming service attempting to serve many users
without a geographically distributed network will inevitably face buffering and low-quality
streams, as its network becomes the primary bottleneck [17].
 A computational bottleneck occurs when a server's processor is consistently overloaded,
resulting in a backlog of pending tasks and increased processing latency. In streaming
systems, typical causes encompass algorithmic approaches that are computationally
demanding (such as complex event processing), suboptimal code execution, or the overhead
associated with data serialization and deserialization across diverse formats. An illustrative
example is an application dedicated to real-time image processing, which saturates the CPU
and consequently hampers overall system performance [17].
 Insufficient Random Access Memory (RAM) can significantly impair system performance.</p>
        <p>When an application's memory demands exceed the available physical RAM, the operating
system employs memory page swapping to disk, a process that is substantially slower than
direct memory access and can drastically reduce system efficiency. In the context of
streaming analytics, this problem frequently occurs with stateful operations, such as
maintaining extensive time-windowed aggregations (e.g., a 24-hour running average of user
activity), which may result in out-of-memory errors if not properly managed [18].
 The speed at which data can be written to and read from persistent storage is a key
performance factor for systems like Apache Kafka, which depend on continuously writing
event logs to disk. Slow disk operations, often associated with traditional Hard Disk Drives
(HDDs), can become a major bottleneck, causing backpressure to spread through the entire
pipeline. Moving to faster storage options, such as Solid-State Drives (SSDs) or NVMe SSDs,
is a common and effective way to address I/O-bound workloads [19].
 Distributed systems rarely operate in isolation. Their performance is often limited by the
downstream services they rely on, such as databases or third-party APIs. A slow database
query, inefficient indexing, or API rate limiting can become the main bottleneck for the entire
streaming application, regardless of how well-optimized the streaming components are [18].</p>
      </sec>
      <sec id="sec-2-6">
        <title>2.6. Classical Approaches of Issue Detection and Their Limitations</title>
        <p>The current forms of anomaly detection rely on statistical and rule-based methods.</p>
        <p>The research article “Developing Big Data anomaly dynamic and static detection algorithms:
AnomalyDSD spark package” [20] utilizes statistical methods. These techniques model normal
behavior with statistical distributions and flag data points that fall into low-probability areas.
Common approaches include using the Z-score or Grubbs' test to spot points that deviate
significantly from the mean, or applying moving averages to smooth data and detect deviations from
a trend. While these methods are easy to implement and highly interpretable, they also have notable
limitations. They usually assume the data follows a specific distribution (e.g., Gaussian), which is
rarely true for complex system telemetry. Additionally, their dependence on fixed, manually set
thresholds makes them fragile; they can't adjust to non-stationary data where the definition of
"normal" changes, resulting in a high rate of false positives and alert fatigue.</p>
        <p>The next research, “A comprehensive survey of anomaly detection techniques for high
dimensional big data” [21], discusses rule-based systems. These systems employ a set of predefined
rules and thresholds, often derived from domain expertise, to identify anomalies. For example, a rule
might say, "alert if CPU utilization &gt; 95% for 5 minutes." They excel at identifying known and
wellunderstood failure modes. However, they need constant manual updates, are inflexible, and cannot
detect new, unforeseen anomalies or "black swan" events, which are common in complex systems.</p>
      </sec>
      <sec id="sec-2-7">
        <title>2.7. Identified Research Gap and Proposed Contribution</title>
        <p>The analysis of existing literature reveals that while the Shift-Left architecture effectively addresses
the latency and redundancy issues of ETL/ELT, it introduces a critical sensitivity to data quality that
is not fully resolved by current, reactive strategies. Therefore, the next chapter proposes an extension
to the Shift-Left architecture: a novel module designed to proactively identify and mitigate these
potential issues much closer to the source, enhancing the resilience and reliability of real-time data
pipelines.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Methodology of Adaptive Issue Detection</title>
      <p>Addressing the identified gaps requires moving beyond a collection of disparate tools and toward a
cohesive, intelligent monitoring platform. This section outlines the conceptual architecture for such
a system, detailing its core principles, internal components, and the end-to-end data flow from
ingestion to insight.</p>
      <sec id="sec-3-1">
        <title>3.1. High-Level System Overview and Core Principles</title>
        <p>The mission of the proposed module is to provide a unified, intelligent monitoring layer that
transcends individual system components, offering a holistic and real-time view of the distributed
system's health. Four core principles guide its design:
 Adaptive: The system must not be static. It must learn the unique behavioral patterns of the
target system and automatically evolve its understanding as those patterns change over time,
effectively handling concept drift.
 Real-Time: For detection to be actionable, it must occur with minimal latency. The
architecture must be optimized for high-throughput, low-latency stream processing.
 Interpretable: The system must not be a "black box." To build operator trust and facilitate
rapid remediation, it must provide clear, understandable explanations for why an anomaly
was flagged. This principle mandates the integration of Explainable AI (XAI).
 Human-in-the-Loop (HITL): The system must be designed as a collaborative partnership
between machines and humans. It must incorporate human expertise to validate anomalies,
correct misclassifications, and guide model retraining, creating a virtuous feedback cycle that
continuously improves performance.</p>
        <p>This architecture represents a shift from a traditional monitoring tool to a comprehensive
monitoring platform, where components for data transport, stream processing, ML inference, and
human interaction are tightly integrated.</p>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. The Architectural Diagram: Internal Components and Data Flow</title>
      </sec>
      <sec id="sec-3-3">
        <title>3.3. A Comparative Analysis of Deep Learning Architectures</title>
        <p>Given the complexity and high dimensionality of the data, deep learning models are the most suitable
candidates. Several architectures are prominent in the field of time-series anomaly detection.
•
•
•</p>
        <p>Recurrent Neural Networks (RNNs) and LSTM Autoencoders. Long Short-Term Memory
(LSTM) networks, a type of RNN, are specifically designed to handle sequential data. Their
internal memory cells enable them to retain information over long periods, making them
effective at learning temporal patterns. In the context of anomaly detection, they are often
employed within an autoencoder architecture. An autoencoder consists of an encoder, which
compresses the input time-series data into a low-dimensional latent representation, and a
decoder, which attempts to reconstruct the original time series from this compressed form.
The model is trained only on normal data. The idea is that the model becomes very good at
reconstructing normal patterns. When it encounters an anomalous pattern, it has not seen
before, it will struggle to reconstruct it accurately, resulting in a high reconstruction error.
This error is then used as the anomaly score. LSTMs have been proven and are effective for
capturing temporal dependencies, including seasonality and trends. While LSTMs
outperform simple RNNs, they can still struggle to capture very long-range dependencies
and complex interactions between different variables in high-dimensional series [22, 23].
Transformer. Originally designed for natural language processing, the Transformer
architecture has achieved notable success in time-series analysis. Its main innovation is the
self-attention mechanism, which enables the model to evaluate the importance of all other
data points in the sequence when processing a single point. This allows it to capture
longrange dependencies and, importantly, the inter-series dependencies (such as the relationship
between CPU usage on node A and network latency on node B) more effectively than RNNs.
The Anomaly Transformer is a specialized version that explicitly models both
"seriesassociation" (temporal patterns) and "prior-association" (expected correlations) to enhance
detection accuracy. While it is the state-of-the-art performance in capturing complex,
longrange, and multivariate dependencies, the transformers are notoriously data-hungry and
computationally expensive to train. Their application in time-series anomaly detection is a
more recent and still-evolving area of research [24, 25].</p>
        <p>Other Architectures. The field is rapidly advancing. Other promising architectures include
Generative Adversarial Networks (GANs), which use a generator/discriminator pair to learn
the distribution of normal data, and very recent developments like Kolmogorov-Arnold
Networks (KAN-AD), which aim to model data using smooth functions, potentially offering
higher efficiency and better resilience to minor fluctuations in normal data [26].</p>
      </sec>
      <sec id="sec-3-4">
        <title>3.4. Proposed Model: A Hybrid, Federated, and Continual Learning Approach</title>
        <p>Synthesizing these requirements leads to a proposal for a hybrid and highly adaptive model
architecture.</p>
        <p>• Core Architecture: A Transformer-based autoencoder is selected as the core model. This
choice is motivated by the need to effectively capture both the long-range temporal
dependencies within individual metric streams and the complex, cross-metric correlations
that are characteristic of distributed system failures.
• Training Paradigm: The system will employ a Federated Continual Learning approach. This
paradigm is perfectly suited to the distributed and dynamic nature of the problem. On
individual clusters or nodes, lightweight local models are trained on local telemetry data.
This preserves data privacy and locality. Federated Aggregation models periodically send
their parameter updates to a central server. The central server uses a continual learning
strategy (e.g., federated averaging combined with regularization techniques to prevent
catastrophic forgetting) to intelligently aggregate these updates into a robust global model.</p>
        <p>This global model captures a holistic understanding of the entire system's health.
• Drift Handling: The central server is responsible for explicit concept drift detection by
monitoring the global data distribution and the performance of the aggregated model. When
significant drift is confirmed (ideally with human validation), it can orchestrate an
accelerated retraining cycle across the federation, ensuring the entire system adapts to the
new normal. This approach creates a scalable, privacy-preserving, and continuously
adapting intelligence core.</p>
        <p>The following table provides a comparative analysis of the leading ML architectures, justifying
the proposed selection.</p>
      </sec>
      <sec id="sec-3-5">
        <title>3.5. The Synergistic Workflow</title>
        <p>A sophisticated machine learning model is only one piece of the puzzle. Its value is only realized
through a well-orchestrated workflow that transforms raw data into actionable insights for human
operators and feeds their expertise back into the system. This section details the end-to-end journey
of data and the synergistic interplay between automated analysis and human intelligence.</p>
        <p>The workflow begins with the continuous collection of telemetry data from the distributed system
(Fig. 5). This raw data, originating from various sources, is fed into a central Apache Kafka bus, which
provides a durable and scalable transport layer. A dedicated stream processing job, probably
implemented with Kafka Streams (but the other options are Apache Flink or Spark), reads from this
bus. The primary task of this job is to feature engineering, which involves converting raw data into
a more meaningful format for the ML model. This involves not only cleaning and normalization but
also creating derived features, such as moving averages, standard deviations over a time window,
and rates of change, which help make anomalous patterns more obvious and easier for the model to
identify.</p>
        <p>The model analyzes each incoming data point (or window of points) and produces a continuous
flow of anomaly scores. A higher score signifies a greater deviation from the learned normal
behavior. A separate logical component, the flagging service, uses these scores and applies a dynamic
threshold. This thresholding step is crucial; a threshold that's too low results in many false positives,
while one that's too high risks missing real incidents. The threshold can also be adaptive, adjusting
based on factors like the time of day, system load, or recent operator feedback. When a score exceeds
the threshold, an anomaly event is generated and stored in a dedicated database, such as
Elasticsearch, making it available for immediate querying by the Control Center.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Experiment</title>
      <p>To validate the effectiveness of the proposed system and justify its implementation, a rigorous and
multi-faceted evaluation framework is essential. A single statistical metric cannot measure success;
it must encompass model accuracy, system performance, and operational efficiency. Furthermore,
the evaluation must go beyond static benchmarks to assess the system's core promise: its ability to
adapt over time.</p>
      <sec id="sec-4-1">
        <title>4.1. Defining Key Performance Indicators</title>
        <p>The evaluation framework should be built around a balanced scorecard of KPIs, grouped into three
distinct categories.</p>
        <p>• Model Accuracy Metrics: These metrics assess the fundamental correctness of the anomaly
detection model's predictions, typically by comparing them against a labeled test set (ground
truth).
o Precision, Recall, and F1-Score: These are the canonical metrics for evaluating
classification tasks. Precision measures the proportion of flagged anomalies that are
actual anomalies (True Positives / (True Positives + False Positives)). High precision is
critical for minimizing false alarms and preventing alert fatigue. Recall measures the
proportion of actual anomalies that the model successfully identified (True Positives /
(True Positives + False Negatives)). High recall is critical for ensuring that important
incidents are not missed. The F1-score is the harmonic mean of precision and recall,
providing a single, balanced measure of accuracy [24].
o AUC-ROC and PR-AUC: The Area Under the Receiver Operating Characteristic
(AUCROC) curve evaluates the model's ability to distinguish between normal and anomalous
classes across all possible threshold settings. More importantly for this use case, the Area
Under the Precision-Recall Curve (PR-AUC) is a superior metric for highly imbalanced
datasets—which are the norm in anomaly detection, as anomalies are rare—as it provides
a better summary of performance on the minority (anomalous) class [26].
• System Performance Metrics: These metrics evaluate the non-functional, operational
characteristics of the deployed system. A model that is perfectly accurate but too slow is
useless in a real-time context.
o Inference Latency: The time elapsed from when the model receives a data point to when
it outputs an anomaly score. This must be consistently low to keep pace with the data
stream.
o Throughput: The number of events or messages the entire system can process per second.</p>
        <p>This measures the system's overall capacity.
o Resource Footprint: The CPU and memory consumption of the deployed ML model and
its surrounding services. This is a key factor in determining the operational cost of the
solution [27, 28].
• Operational and Business Metrics: These KPIs measure the system's real-world impact and
value to the organization.
o Human Intervention Rate: The frequency with which human feedback is required. A
decreasing rate over time is a strong indicator that the model is learning effectively from
the feedback and becoming more autonomous.
o Mean Time to Resolution (MTTR): The average time from when an alert is generated to
when the underlying issue is resolved. A reduction in MTTR suggests that the system's
alerts are more accurate, interpretable, and actionable.</p>
        <p>To demonstrate the value of the proposed adaptive system, its performance must be compared
against simpler, more traditional baselines.</p>
        <p>• Static Thresholding: The most basic baseline, representing the legacy approach. Alerts are
triggered if a single key metric (e.g., CPU utilization) exceeds a fixed, manually set threshold.</p>
        <p>This baseline will highlight the limitations of non-ML approaches.
• Classical Unsupervised Model: A non-adaptive ML model, such as an Isolation Forest or
OneClass SVM, trained once on an initial batch of historical data. This baseline will demonstrate
the value of the adaptive and continual learning components of the proposed system, as this
model's performance is expected to degrade over time due to concept drift.</p>
      </sec>
      <sec id="sec-4-2">
        <title>4.2. Datasets and Scenarios</title>
        <p>A comprehensive evaluation requires a diverse data strategy. To this end, the experiment will employ
a combination of established, publicly available real-world benchmarks and purpose-built synthetic
datasets. This dual approach enables both validation of the system's performance against the state of
the art and a controlled, scientific stress test of its specific adaptive mechanisms.</p>
        <p>While real-world datasets are essential for benchmarking and demonstrating generalizability,
they are often insufficient for rigorously validating the core adaptive claims of this research. Real
datasets, such as NAB [25] or Yahoo S5 [26], contain labeled anomalies, but any concept drifts within
them are emergent, unlabeled properties of the data. It is difficult to scientifically prove that the
system correctly adapted to a drift if the type, timing, and magnitude of that drift are not known
ground truths. To overcome this, the use of synthetic data is indispensable. It allows for a controlled
experiment where concept drift is not an observation but a manipulated variable. The tool CanGene
[27] or GenIAS [28] is designed for this exact purpose, enabling the injection of specific, labeled
anomalies and concept drifts (e.g., abrupt, gradual) into a baseline time series. Therefore, the
experimental design must include scenarios based on synthetic data to provide the most substantial
evidence regarding the system's adaptability. The real-world datasets serve to ground these findings
and demonstrate their practical applicability.</p>
      </sec>
      <sec id="sec-4-3">
        <title>4.3. Experimental Scenarios</title>
        <p>A series of well-defined experimental scenarios will be executed to test specific hypotheses about
the system's capabilities. Table 2 outlines this plan.</p>
        <sec id="sec-4-3-1">
          <title>Key Metrics to Analyze</title>
        </sec>
        <sec id="sec-4-3-2">
          <title>NAB, Yahoo Evaluate raw detection accuracy on Precision, Recall, F1S5 standard, public benchmarks to Score (with Point establish a performance baseline Adjustment) against the state of the art.</title>
          <p>High-volume Measure system throughput, end- End-to-end Latency (ms),
Synthetic to-end latency, and resource Throughput (events/sec),
utilization under varying levels of CPU/GPU Utilization (%)
sustained data load
3 Resilience Synthetic Test the system's ability to recover Time-to-Adaptation
to Abrupt (with and adapt after a sudden, (TTA), False Positive Rate
Drift injected permanent change in the (FPR) during drift,
F1abrupt drift) underlying data distribution. Score post-adaptation
4 Resilience Synthetic Test the system's ability to track a F1-Score over time, Plot
to (with slow-changing data distribution of Dynamic Threshold vs.
Gradual injected without generating excessive false Mean Anomaly Score
Drift gradual drift) alarms.</p>
          <p>The formal definitions of these key metrics are summarized in Table 3 below to ensure clarity
and reproducibility.</p>
        </sec>
        <sec id="sec-4-3-3">
          <title>The harmonic mean of Precision and Recall, providing a single score that balances both F1-Score calculated using Point-Adjusted TP, FP, and FN counts. A more practical F1-Score for time-series where anomalies have duration</title>
          <p>The end-to-end processing time for a single event</p>
          <p>The time required for the system to recover from a sudden concept drift</p>
          <p>Each experimental scenario defined in Table 3 will be executed on a dedicated Kubernetes cluster
to ensure isolation of resources. A data replay application will read from the specified dataset files
and stream the events into the telemetry-raw Kafka topic at a controlled rate, simulating a live data
feed. During each run, performance and accuracy metrics will be continuously logged to a
monitoring stack (e.g., Prometheus for metrics, Grafana for visualization). The output of the Flink
job (anomaly alerts) will be consumed and compared against the ground-truth labels for the
respective dataset to calculate accuracy scores.</p>
          <p>We establish a baseline for detection accuracy using the standard Numenta Anomaly Benchmark
(NAB) and Yahoo S5 datasets, which provide labeled, real-world server and application telemetry for
direct comparison against state-of-the-art models. To test critical real-world capabilities beyond
simple accuracy, we also generated three specific synthetic datasets. A high-throughput stream of
up to 25,000 events per second was used to measure scalability and performance under
productionlevel load.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>5. Results</title>
      <p>To establish a credible baseline, we first evaluated Ada-TAD's raw anomaly detection accuracy on
two widely recognized public datasets: the Numenta Anomaly Benchmark (NAB) v1.1 and the Yahoo
S5 dataset. We followed the standard evaluation protocol for these benchmarks, including the use of
point-adjustment to reward early detection and penalize detections within the same anomaly
window. (see Table 4).</p>
      <p>The Performance &amp; Scalability experiment measured the system's non-functional characteristics
under a high-volume synthetic data stream (See Table 5), simulating a production environment. The
load was incrementally increased from 5,000 to 25,000 events per second.</p>
      <p>The Resilience to Abrupt Concept Drif scenario tested the system’s ability to recover after a
sudden, permanent change in the data distribution (Table 6). We synthesized a data stream and, at a
designated point, introduced an abrupt drift by changing the mean and variance of two key metrics.</p>
      <p>The final experiment (Resilience to Gradual Concept Drift) evaluated the system's ability to track
a slow-moving data distribution, a common scenario in production systems where performance
characteristics change over weeks or months. We introduced a slow, linear increase in the baseline
CPU and memory usage of our synthetic application.</p>
    </sec>
    <sec id="sec-6">
      <title>6. Discussion</title>
      <p>The results in Table 4 show that Ada-TAD achieves top-tier performance, surpassing the static
Isolation Forest in F1-Score on both benchmarks. The very high recall combined with poor precision
of Static Thresholding highlights its tendency to produce too many false positives, making it
unusable for production. Ada-TAD's balanced precision and recall emphasize its effectiveness even
before its adaptive features are evaluated.</p>
      <p>As expected for the Performance &amp; Scalability scenario, the computational complexity of the
Transformer architecture causes higher latency and resource use for Ada-TAD compared to the
lightweight Isolation Forest. However, its throughput of approximately 22,000 events per second on
a single commodity GPU shows its suitability for high-volume streaming systems, and its latency
stays well within acceptable limits for real-time monitoring. The primary trade-off for the improved
accuracy and adaptability seen in later experiments is the cost of additional resources.</p>
      <p>The results of the System Resilience to Abrupt Drift scenario are clear. When the drift occurred,
the static Isolation Forest model started producing a steady flow of false positives because its
understanding of "normal" was now outdated. Its F1-Score dropped sharply, and its False Positive
Rate became unmanageable. In contrast, Ada-TAD detected the change, and although it produced a
brief burst of anomalies, its retraining mechanism updated the model weights and recalibrated the
dynamic threshold. It adapted to the new normal in just 12 minutes, restoring its high F1 Score and
demonstrating strong resilience.</p>
      <p>The left side of Figure 6 illustrates the performance decline of the non-adaptive model. As the
data distribution gradually shifted, the static perspective of the Isolation Forest became less accurate,
causing a steady drop in its F1-Score. Meanwhile, Ada-TAD consistently maintained a high F1-Score
throughout the experiment.</p>
      <p>The right side of Figure 6 shows how this resilience works. The plot illustrates the average
reconstruction error (anomaly score) of normal data points increasing gradually due to drift. The key
point is how Ada-TAD's dynamic anomaly threshold smoothly follows this change, rising in sync
with the anomaly scores. This helps the system avoid false alarms on the "new normal,"
demonstrating a smart and effective way to adapt to gradual changes that static models can't match.</p>
    </sec>
    <sec id="sec-7">
      <title>7. Conclusions</title>
      <p>This research tackled the key challenge of anomaly detection in dynamic, high-volume, distributed
data streaming systems, where concept drift makes traditional static monitoring methods ineffective.
We showed that common approaches, such as fixed thresholding and non-adaptive machine learning
models like Isolation Forest, are essentially fragile; their performance drops sharply with changing
data distributions, causing a poor balance between too many false alarms and missed critical events.</p>
      <p>Our proposed solution, the Adaptive Issue Detection module, effectively overcomes these
limitations. The experimental results offer strong evidence of its superiority in various areas. We
have demonstrated that:
• Ada-TAD achieves top-tier accuracy on well-known public benchmarks, offering a good
performance baseline.
• More importantly, it shows strong resilience against both gradual and sudden concept drift.</p>
      <p>By continuously learning from the data stream and utilizing a flexible anomaly threshold,
the system independently adapts to new patterns of normal behavior, maintaining a
consistently high F1-score where static models often fall short.
• Despite its architectural sophistication, the system is suitable for production environments,
capable of managing high-throughput data streams with latencies appropriate for real-time
monitoring.</p>
      <p>The main contribution of this work is a comprehensive system that shifts from reactive,
highmaintenance monitoring to autonomous, adaptive issue detection. The practical impact for
engineering organizations is a significant reduction in operational workload. By offering more
accurate and reliable alerts, Ada-TAD directly reduces alert fatigue, shortens Mean Time to
Resolution (MTTR), and ultimately leads to more resilient and dependable services.</p>
      <p>While the results are promising, we acknowledge certain limitations that present opportunities
for future research. The improved accuracy and adaptability of Ada-TAD come with higher
computational costs compared to simpler models. Although manageable, further exploration of
optimization techniques such as quantization and pruning could decrease resource requirements,
making the system accessible to a broader range of applications. Additionally, although our system
is effective at detecting anomalies, future efforts should focus on improving its explainability. Lastly,
expanding the framework to process and connect multi-modal telemetry—combining metrics with
logs and traces—offers an exciting direction for developing an even more powerful and
contextaware issue detection system.</p>
    </sec>
    <sec id="sec-8">
      <title>Declaration on Generative AI</title>
      <sec id="sec-8-1">
        <title>The authors have not employed any Generative AI tools.</title>
      </sec>
    </sec>
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