Searcharxiv⌕ Search

arXiv subjects

Qingzhi Liu

Publications and source records attributed to Qingzhi Liu.

12 recordsLinked to original sources

SciText2Eq: Assessing LLMs for Explainable Equation Generation for Scientific Creativity

This work investigates the ability of large language models (LLMs) to generate mathematical equations from scientific texts. Prior work faces challenges in unstructured grounding, multi-equation dependency, and humanaligned evaluation. To this end, we construct a dataset of AI research papers, pairing contextual passages with ground-truth equations and variable descriptions. We develop an explainable equation generation workflow and evaluate it across diverse open- and closed-source LLM backbones. We introduce an evaluation protocol combining automatic metrics, LLM-based rubrics, and human judgments to assess accuracy, explainability, and human-LLM alignment. Results indicate that LLMs perform moderately on lexical- and syntactic-based similarity, while struggling with semantic accuracy. Comparisons between LLM-based evaluations and human judgments reveal limited alignment, highlighting challenges in using LLMs to assess equation quality. These findings offer insights for improving equation generation models and developing more reliable evaluation methods for scientific text. We provide code and data for reproducibility.

cs.AI↗

A Time-Varying and Covariate-Dependent Correlation Model for Multivariate Longitudinal Studies

In multivariate longitudinal studies, associations between outcomes often exhibit time-varying and individual level heterogeneity, motivating the modeling of correlations as an explicit function of time and covariates. However, most existing methods for correlation analysis fail to simultaneously capture the time-varying and covariate-dependent effects. We propose a Time-Varying and Covariate-Dependent (TiVAC) correlation model that jointly allows covariate effects on correlation to change flexibly and smoothly across time. TiVAC employs a bivariate Gaussian model where the covariate-dependent correlations are modeled semiparametrically using penalized splines. We develop a penalized maximum likelihood-based Newton-Raphson algorithm, and inference on time-varying effects is provided through simultaneous confidence bands. Simulation studies show that TiVAC consistently outperforms existing methods in accurately estimating correlations across a wide range of settings, including binary and continuous covariates, sparse to dense observation schedules, and across diverse correlation trajectory patterns. We apply TiVAC to a psychiatric case study of 291 bipolar I patients, modeling the time-varying correlation between depression and anxiety scores as a function of their clinical variables. Our analyses reveal significant heterogeneity associated with gender and nervous-system medication use, which varies with age, revealing the complex dynamic relationship between depression and anxiety in bipolar disorders.

stat.ME↗

Resource Management Schemes for Cloud-Native Platforms with Computing Containers of Docker and Kubernetes

Businesses have made increasing adoption and incorporation of cloud technology into internal processes in the last decade. The cloud-based deployment provides on-demand availability without active management. More recently, the concept of cloud-native application has been proposed and represents an invaluable step toward helping organizations develop software faster and update it more frequently to achieve dramatic business outcomes. Cloud-native is an approach to build and run applications that exploit the cloud computing delivery model's advantages. It is more about how applications are created and deployed than where. The container-based virtualization technology, such as Docker and Kubernetes, serves as the foundation for cloud-native applications. This paper investigates the performance of two popular computational-intensive applications, big data, and deep learning, in a cloud-native environment. We analyze the system overhead and resource usage for these applications. Through extensive experiments, we show that the completion time reduces by up to 79.4% by changing the default setting and increases by up to 96.7% due to different resource management schemes on two platforms. Additionally, the resource release is delayed by up to 116.7% across different systems. Our work can guide developers, administrators, and researchers to better design and deploy their applications by selecting and configuring a hosting platform.

cs.DC↗

Trustworthy AI Psychotherapy: Multi-Agent LLM Workflow for Counseling and Explainable Mental Disorder Diagnosis

LLM-based agents have emerged as transformative tools capable of executing complex tasks through iterative planning and action, achieving significant advancements in understanding and addressing user needs. Yet, their effectiveness remains limited in specialized domains such as mental health diagnosis, where they underperform compared to general applications. Current approaches to integrating diagnostic capabilities into LLMs rely on scarce, highly sensitive mental health datasets, which are challenging to acquire. These methods also fail to emulate clinicians' proactive inquiry skills, lack multi-turn conversational comprehension, and struggle to align outputs with expert clinical reasoning. To address these gaps, we propose DSM5AgentFlow, the first LLM-based agent workflow designed to autonomously generate DSM-5 Level-1 diagnostic questionnaires. By simulating therapist-client dialogues with specific client profiles, the framework delivers transparent, step-by-step disorder predictions, producing explainable and trustworthy results. This workflow serves as a complementary tool for mental health diagnosis, ensuring adherence to ethical and legal standards. Through comprehensive experiments, we evaluate leading LLMs across three critical dimensions: conversational realism, diagnostic accuracy, and explainability. Our datasets and implementations are fully open-sourced.

cs.HC↗

Differentiate Quality of Experience Scheduling for Deep Learning Inferences with Docker Containers in the Cloud

With the prevalence of big-data-driven applications, such as face recognition on smartphones and tailored recommendations from Google Ads, we are on the road to a lifestyle with significantly more intelligence than ever before. Various neural network powered models are running at the back end of their intelligence to enable quick responses to users. Supporting those models requires lots of cloud-based computational resources, e.g., CPUs and GPUs. The cloud providers charge their clients by the amount of resources that they occupy. Clients have to balance the budget and quality of experiences (e.g., response time). The budget leans on individual business owners, and the required Quality of Experience (QoE) depends on usage scenarios of different applications. For instance, an autonomous vehicle requires an real-time response, but unlocking your smartphone can tolerate delays. However, cloud providers fail to offer a QoE-based option to their clients. In this paper, we propose DQoES, differentiated quality of experience scheduler for deep learning inferences. DQoES accepts clients' specifications on targeted QoEs, and dynamically adjusts resources to approach their targets. Through the extensive cloud-based experiments, DQoES demonstrates that it can schedule multiple concurrent jobs with respect to various QoEs and achieve up to 8x times more satisfied models when compared to the existing system

cs.DC↗

MPC-CSAS: Multi-Party Computation for Real-time Privacy-preserving Speed Advisory Systems

As a part of Advanced Driver Assistance Systems (ADASs), Consensus-based Speed Advisory Systems (CSAS) have been proposed to recommend a common speed to a group of vehicles for specific application purposes, such as emission control and energy management. With Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) technologies and advanced control theories in place, state-of-the-art CSAS can be designed to get an optimal speed in a privacy-preserving and decentralized manner. However, the current method only works for specific cost functions of vehicles, and its execution usually involves many algorithm iterations leading long convergence time. Therefore, the state-of-the-art design method is not applicable to a CSAS design which requires real-time decision making. In this paper, we address the problem by introducing MPC-CSAS, a Multi-Party Computation (MPC) based design approach for privacy-preserving CSAS. Our proposed method is simple to implement and applicable to all types of cost functions of vehicles. Moreover, our simulation results show that the proposed MPC-CSAS can achieve very promising system performance in just one algorithm iteration without using extra infrastructure for a typical CSAS.

eess.SY↗

Speculative Container Scheduling for Deep Learning Applications in a Kubernetes Cluster

In the past decade, we have witnessed a dramatically increasing volume of data collected from varied sources. The explosion of data has transformed the world as more information is available for collection and analysis than ever before. To maximize the utilization, various machine and deep learning models have been developed, e.g. CNN [1] and RNN [2], to study data and extract valuable information from different perspectives. While data-driven applications improve countless products, training models for hyperparameter tuning is still a time-consuming and resource-intensive process. Cloud computing provides infrastructure support for the training of deep learning applications. The cloud service providers, such as Amazon Web Services [3], create an isolated virtual environment (virtual machines and containers) for clients, who share physical resources, e.g., CPU and memory. On the cloud, resource management schemes are implemented to enable better sharing among users and boost the system-wide performance. However, general scheduling approaches, such as spread priority and balanced resource schedulers, do not work well with deep learning workloads. In this project, we propose SpeCon, a novel container scheduler that is optimized for shortlived deep learning applications. Based on virtualized containers, such as Kubernetes [4] and Docker [5], SpeCon analyzes the common characteristics of training processes. We design a suite of algorithms to monitor the progress of the training and speculatively migrate the slow-growing models to release resources for fast-growing ones. Specifically, the extensive experiments demonstrate that SpeCon improves the completion time of an individual job by up to 41.5%, 14.8% system-wide and 24.7% in terms of makespan.

cs.DC↗

BEH: Indoor Batteryless BLE Beacons using RF Energy Harvesting for Internet of Things

Indoor beacon system is a cornerstone of internet of things. Until now, most of the research effort has focused on achieving various applications based on beacon communication. However, the power consumption on beacon devices becomes the bottleneck for the large-scale deployments of indoor networks. On one hand, the size of beacon devices is required to be small enough for easy deployment, which further limits the size of battery. On the other hand, replacing the batteries of the beacon devices could lead to high maintenance costs. It is important to provide them with full energy autonomy. To tackle this problem we propose BEH: an indoor beacon system aimed at operating perpetually without batteries. Our contributions are twofold. Firstly, we propose four methods to increase the utilization efficiency of harvested RF energy in the beacon system, by which the energy consumption level becomes low enough to fit within the energy harvesting budget. Secondly, we implement BEH using Bluetooth Low Energy (BLE) and Radio Frequency (RF) energy harvesting devices, and test BEH extensively in a laboratory environment. Our test results show that BEH can enable perpetual lifetime operation of mobile and static BLE beacon devices in a (16 m$^{\text{2}}$) room. The average value of packet reception rate achieves more than 99% in the best case.

cs.NI↗

WiPLoc: Perpetual Indoor Localization with RF Wireless Power Transfer

Indoor localization is a cornerstone of mobile services. Until now most of the research effort has focused on achieving sub-meter localization accuracy because many mobile applications depend on precise localization measurements. In some scenarios, however, it is required to trade location accuracy for system maintainability. For example, in large-scale deployments of indoor networks, such as item-monitoring in smart buildings, attaining room-level localization accuracy may be sufficient, but replacing the batteries of the devices used for localization could lead to high operational costs. As indoor localization systems grow in popularity it will be important to provide them with full energy autonomy. To tackle this problem we propose WiPLoc: an indoor localization system aimed at operating perpetually without batteries. Our contributions are twofold. First, we propose a novel localization method that exploits capture effect and orthogonal codes to operate at energy levels that are low enough to operate within the energy budget provided by long-range wireless power transmission. Second, we implement WiPLoc using off-the-shelf components and test it extensively in a laboratory environment. Our test results show that with WiPLoc one wireless charger per (16 m$^{\text{2}}$) room can enable perpetual lifetime operation of mobile objects requiring localization with an average accuracy of almost 90%.

cs.NI↗

BLISP: Enhancing Backscatter Radio with Active Radio for Computational RFIDs

We demonstrate the world's first hybrid radio platform which combines the strengths of active radio (long range and robustness to interference) and Computational RFIDs (low power consumption). We evaluate the Wireless Identification and Sensing Platform (WISP), an EPC C1G2 standard-based, Computational RFID backscatter radio, against Bluetooth Low Energy (BLE) and show (theoretically and experimentally) that WISP in high channel attenuation conditions is less energy efficient per received byte than BLE. Exploiting this observation we design a simple switching mechanisms that backs off to BLE when radio conditions for WISP are unfavorable. By a set of laboratory experiments, we show that our proposed hybrid active/backscatter radio obtains higher goodput than WISP and lower energy consumption than BLE as stand-alone platforms, especially when WISP is in range of an RFID interrogator for the majority of the time. Simultaneously, our proposed platform is as energy efficient as BLE when user is mostly out of RFID interrogator range.

cs.NI↗

Safe and Secure Wireless Power Transfer Networks: Challenges and Opportunities in RF-Based Systems

RF-based wireless power transfer networks (WPTNs) are deployed to transfer power to embedded devices over the air via RF waves. Up until now, a considerable amount of effort has been devoted by researchers to design WPTNs that maximize several objectives such as harvested power, energy outage and charging delay. However, inherent security and safety issues are generally overlooked and these need to be solved if WPTNs are to be become widespread. This article focuses on safety and security problems related WPTNs and highlight their cruciality in terms of efficient and dependable operation of RF-based WPTNs. We provide a overview of new research opportunities in this emerging domain.

cs.NI↗

Green Wireless Power Transfer Networks

A Wireless Power Transfer Network (WPTN) aims to support devices with cable-less energy on-demand. Unfortunately, wireless power transfer itself-especially through radio frequency radiation rectification-is fairly inefficient due to decaying power with distance, antenna polarization, etc. Consequently, idle charging needs to be minimized to reduce already large costs of providing energy to the receivers and at the same time reduce the carbon footprint of WPTNs. In turn, energy saving in a WPTN can be boosted by simply switching off the energy transmitter when the received energy is too weak for rectification. Therefore in this paper we propose, and experimentally evaluate, two "green" protocols for the control plane of static charger/mobile receiver WPTN aimed at optimizing the charger workflow to make WPTN green. Those protocols are: 'beaconing', where receivers advertise their presence to WPTN, and 'probing' exploiting the receiver feedback from WTPN on the level of received energy. We demonstrate that both protocols reduce the unnecessary WTPN uptime, however trading it for the reduced energy provision, compared to the base case of 'WPTN charger always on'. For example, our system (in our experiments) saves at most approx. 80% of energy and increases 5.5 times the efficiency with only approx. 17% less energy possibly harvested.

cs.NI↗