About

Shahram Ghandeharizadeh received his Ph.D. degree in Computer Science from the University of Wisconsin, Madison, in 1990, and his Master's and Bachelor's degrees from the same institution in 1987 and 1985, respectively. Since then, he has been a faculty member at the University of Southern California. His research interests include the design, implementation, and evaluation of novel architectures for high-performance data-intensive applications, intelligent 3D multimedia displays, multimedia-based social networking systems, transaction processing systems, and benchmarking. He has served on the organizing committees of numerous conferences, including as general chair of Holodecks 2026 and VLDB 2019, and program co-chair of the ACM Multimedia 2026 Brave New Ideas track. Dr. Ghandeharizadeh's activities are supported by grants from organizations such as the National Science Foundation, Oracle, Microsoft, BMC Software, and Hewlett-Packard. He is a distinguished member of the ACM and the director of the database laboratory at USC. His professional service includes membership on the ACM SIGMOD executive committee and serving as the Editor-in-Chief of ACM SIGMOD DiSC from 2003 to 2006. He is also involved in organizing events focused on immersive technologies, including workshops and international conferences, emphasizing the development of 3D immersive environments and related enabling technologies.

Research topics

• Computer Science
• Artificial Intelligence
• Optics
• Computer graphics (images)
• Computer vision
• Physics

Selected publications

• DiStash: A Disaggregated Multi-stash Transactional Key-Value Store

  Lecture notes in computer science · 2026-01-01

  book-chapterSenior author
  PublisherDOI

• Techniques to Conceal Dark Standby Flying Light Specks

  ACM Transactions on Multimedia Computing Communications and Applications · 2025-04-02 · 5 citations

  articleSenior author

  A Flying Light Speck (FLS) is a small drone configured with light sources to illuminate different colors and textures. A swarm of FLSs illuminates complex 3D multimedia shapes in a fixed volume, a 3D display. An FLS is a mechanical device. Its failure is the norm rather than an exception, causing a point of an illumination to go dark. In this article, we use reliability groups with dark standby FLSs to minimize the duration of time a point remains dark. We introduce three techniques to prevent a dark standby FLS from obstructing the user’s Field of View (FoV). All three move the FLS out of the user’s FoV. One technique, Suspend:Closest, maximizes the utility of a standby FLS while preventing it from obstructing the user’s FoV.

  PublisherDOI

• Illuminating English Letters Using a Flying Light Speck

  2025-10-27 · 2 citations

  articleOpen accessSenior author

  This paper presents the design and implementation of a Flying Light Speck (FLS) to illuminate English letters. The FLS uses its onboard camera and computing to localize and follow a trajectory to illuminate a letter. We evaluate the illuminations quantitatively and qualitatively. The latter is based on an IRB approved human subject study with 20 participants. The obtained results show a 42 to 56 millimeter error that impacts the detection of letters. A key finding is that the order in which the illumination of letters is presented to subjects has a significant effect on detection duration.

  PublisherOA PDFDOI

• Integration of 3D FLS Displays with 3D Authoring Tools

  2025-10-25 · 3 citations

  articleOpen accessSenior author
  PublisherDOI

• Reproducibility Companion Paper: Swarical: An Integrated Hierarchical Approach to Localizing Flying Light Specks

  2025-10-25 · 1 citations

  articleOpen access

  This companion paper provides artifacts and instructions on replicating the experiments in the ACM Multimedia 2024 paper entitled ''Swarical: An Integrated Hierarchical Approach to Localizing Flying Light Specks.'' Swarm-based hierarchical, Swarical, is a localization technique that enables miniature drones, Flying Light Specks (FLSs), to accurately and efficiently localize and illuminate complex 2D and 3D shapes. It consists of two components, an offline planner and an online localization technique that executes on an FLS. The offline planner uses the FLS sensor specification for positioning to convert mesh files into swarms of FLSs. Some FLSs are dark and used only for localization. We reported the online localization technique to be fast and highly accurate. We describe how to reproduce this finding using our artifacts.

  PublisherDOI

• Memory Hierarchy Design for Caching Middleware in the Age of NVM

  ArXiv.org · 2025-06-05 · 4 citations

  preprintOpen access1st authorCorresponding

  Advances in storage technology have introduced Non-Volatile Memory, NVM, as a new storage medium. NVM, along with Dynamic Random Access Memory (DRAM), Solid State Disk (SSD), and Disk present a system designer with a wide array of options in designing caching middleware. Moreover, design decisions to replicate a data item in more than one level of a caching memory hierarchy may enhance the overall system performance with a faster recovery time in the event of a memory failure. Given a fixed budget, the key configuration questions are: Which storage media should constitute the memory hierarchy? What is the storage capacity of each hierarchy? Should data be replicated or partitioned across the different levels of the hierarchy? We model these cache configuration questions as an instance of the Multiple Choice Knapsack Problem (MCKP). This model is guided by the specification of each type of memory along with an application's database characteristics and its workload. Although MCKP is NP-complete, its linear programming relaxation is efficiently solvable and can be used to closely approximate the optimal solution. We use the resulting simple algorithm to evaluate design tradeoffs in the context of a memory hierarchy for a Key-Value Store (e.g., memcached) as well as a host-side cache (e.g., Flashcache). The results show selective replication is appropriate with certain failure rates and workload characteristics. With a slim failure rate and frequent data updates, tiering of data across the different storage media that constitute the cache is superior to replication.

  PublisherOA PDFDOI

• Flying Light Specks: Dronevision, Holodecks and Spatial Computing

  2025-10-20 · 3 citations

  article1st authorCorresponding
  PublisherDOI

• One-Hop Sub-Query Result Caches for Graph Database Systems

  arXiv (Cornell University) · 2024-12-06

  preprintOpen accessSenior author

  This paper introduces a novel one-hop sub-query result cache for processing graph read transactions, gR-Txs, in a graph database system. The one-hop navigation is from a vertex using either its in-coming or out-going edges with selection predicates that filter edges and vertices. Its cache entry identifies a unique one-hop sub-query (key) and its result set consisting of immutable vertex ids (value). When processing a gR-Tx, the query processor identifies its sequence of individual one-hop sub-queries and looks up their results in the cache. A cache hit fetches less data from the storage manager and eliminates the requirement to process the one-hop sub-query. A cache miss populates the cache asynchronously and in a transactional manner, maintaining the separation of read and write paths of our transactional storage manager. A graph read and write transaction, gRW-Tx, identifies the impacted cache entries and either deletes or updates them. Our implementation of the cache is inside the graph query processing engine and transparent to a user application. We evaluate the cache using our eCommerce production workload and with rules that re-write graph queries to maximize the performance enhancements observed with the cache. Obtained results show the cache enhances 95th and 99th percentile of query response times by at least 2x and 1.63x, respectively. When combined with query re-writing, the enhancements are at least 2.33x and 4.48x, respectively. An interesting result is the significant performance enhancement observed by the indirect beneficiaries of the cache, gRW-Txs and gR-Txs that do not reference one-hop sub-queries. The cache frees system resources to expedite their processing significantly.

  PublisherOA PDFDOI

• Reliability Groups with Standby Flying Light Specks

  2024-04-15 · 5 citations

  articleOpen accessSenior author

  A Flying Light Speck, FLS, is a miniature sized drone configured with light sources to illuminate different colors and textures. A swarm of FLSs illuminates complex 3D multimedia shapes in a fixed volume, a 3D display. An FLS is a mechanical device. Its failure is the norm rather than an exception, causing a point of an illumination to go dark. In this paper, we use reliability groups with dark standby FLSs to minimize the duration of time a point remains dark. This study makes two novel contributions. First, it compares a centralized and a decentralized algorithm to form groups, demonstrating the superiority of the centralized technique. Second, it detects when the dark standby FLSs may obstruct the user's field of view and relocates them with minimal impact on their provided benefit.

  PublisherOA PDFDOI

• Force-Feedback Through Touch-based Interactions With A Nanocopter

  2024-04-07 · 8 citations

  article

  The choice of haptic rendering tools plays a pivotal role in the perception of the simulated kinesthetic feedback. This paper introduces a novel approach using Crazyflie-based quadcopters as haptic rendering devices to simulate virtual stiffness. By designing a specialized cage and implementing control using Crazyswarm and both centralized and decentralized localization techniques, we implemented the smallest drone-based direct-touch encounter-type haptic feedback device. We evaluated three different proportional control levels, with each level simulating a different stiffness based on a distance-to-thrust response. We conducted a user study, which revealed that even with only 21 grams of the force output range, participants could distinguish between the proportional levels, perceiving higher proportional levels as increased stiffness. We also identified distinct vibration characteristics between cages made of different 3D printing materials. Our findings suggest that quadcopters can be effectively used as haptic tools, offering a controllable kinesthetic feedback system.

  PublisherDOI

Recent grants

• EAGER: Prototyping Touch with FLS-Matter

  NSF · $250k · 2023–2025

• Management and Processing of Continuous Streams from Moving Sensors

  NSF · $300k · 2003–2007

Frequent coauthors

• Cyrus Shahabi

  26 shared

• Roger Zimmermann

  21 shared

• Sumita Barahmand

  University of Southern California

  17 shared

• Hamed Alimohammadzadeh

  University of Southern California

  15 shared

• David J. DeWitt

  15 shared

• Shahin Shayandeh

  Apple (United States)

  13 shared

• Seon Ho Kim

  Seoul National University of Science and Technology

  11 shared

• Weifeng Shi

  Shanghai Jiao Tong University

  10 shared

Education

• B.S., M.S., Ph.D., Computer Sciences

  University of Wisconsin Madison

  1990

Awards & honors

• NSF Young Investigator Award (1992)
• USC Annenberg Fellow (2005)
• ACM ACM-SIGMM (Multimedia) Award (2000)
• ACM ACM-SIGMOD Service Award (1999)
• Okawa Foundation Information Technology Fellow (1999)