Category Archives: research

Looking for new Ph.D. Students to Join My Research Lab

RED Talk Hendler and Pazour FINAL

Modern distribution systems need to fulfill a wide variety of requests quickly with little warning in small units to many dispersed locations at low costs.  This is fundamentally different than yesterday’s demand, which aggregated at fixed (store) locations.  Thus, today’s supply chains are optimized for yesterday’s customers.

To close the gap between current supply chain operations and customer expectations, our research team rethinks supply chain design.  We are exploring creative solutions around on-demand warehousing and crowdsourced deliveries, in which marketplaces provide access to resources (when and where they are needed), rather than owning them.  This creates a dynamic supply network, able to respond to changing demand requirements.  But, such systems are inherently more complex than traditional systems. To address these challenges, we are researching new network design models to capture on-demand business models (for a quick overview,  check out Flexe’s videos ) and will use these models to quantity the benefit in terms of access to scale, reduced commitment granularity, and reduced capacity granularity.  We are also conducting basic research on how best to provide a set of decentralized suppliers choice to entice them to provide access to their resources on-demand. By tapping into underutilized supply capacity, supplier choice can increase participation – and thus capacity –  and provides agility through more flexible use of suppliers.  This can improve e-commerce profitability and enable a new on-demand volunteer base.  Our research team has partnered with community nonprofits to test how on-demand grocery delivery systems for mobility-restricted clients can help address the needs of residents living in food deserts.

Sound interesting?  If so, I encourage you to apply to join my research lab.  I’m looking for talented, curious new Ph.D. students.   Check out my website (https://jenpazour.wordpress.com/) to learn more about our research and team.  Feel free to contact me (pazouj@rpi.edu) if you have questions or to request a SKYPE appointment to learn more.

Earning a Ph.D. fundamentally changed — for the better both — my professional and personal paths in life.  I encourage you to think about a Ph.D. I also entered the Ph.D. program pretty naive.  So below I provide what I (now) believe is needed to be successful in a Ph.D. program, and a research career beyond, as well as reasons why I think RPI’s Industrial and Systems department is a good place to be a Ph.D. student.

First, a Ph.D. is a research degree.  This is in contrast to bachelor degrees and (today) most masters degrees, which are coursework degrees.  Getting good grades in school is not sufficient to succeeding in graduate school.

So what do I believe it takes to succeed in graduate school?  Well, first, you have to be ready to fail.  Research is about discovering something new or doing something that has never been done before.  There are no answers at the back of the book.  The discovery process is exciting, but also non-linear.  Many of the things we try, do not work.  You have to be OK with this.

But, you also need to succeed enough to outweigh all the failing.  Bob Dylan, the great Nobel prize-winning poet, summed up life in academia well, “She knows there’s no success like failure.  And that failure’s no success at all.”  You need to be excited about what you are doing and willing to put in the time and follow through the failures to get to success.  Because ultimately to graduate, you need to succeed.  Your research needs to make contributions.  Failure is not enough.  Follow through is critical.  You need to be able to make yourself do the mundane (whether that’s writing up results, responding to reviewers comments, writing up research funding reports, or responding to emails).  In fact, to be successful as a faculty member, I believe you need to be efficient at the mundane.  You need to be able to efficiently juggle many different projects, requests, and emails.

To succeed at a Ph.D. it is (in my opinion) necessary to be able to do both: to (1) excel at new idea generation and to bounce back after failure, and to (2) follow through (and even be efficient) with mundane tasks.  While you do not need to an expert at either of these as an incoming Ph.D. student,  you need to work at and keep improving on both types of tasks.  Therefore, skills I am particularly looking for in Ph.D. Students:

  1. Kind Human Being
  2. Grit
  3. Curiosity
  4. Writing and Logic Skills
  5. Communication Skills
  6. Ability to think about and improve our understanding of complex problems
  7. Mathematical ability
  8. Coding background
  9. Ability to deal with uncertainty.
  10. Critical Thinking.

Reasons why I would like to be a graduate student at Rensselaer’s Industrial and Systems Engineering department:

  1. It’s a small co-hort. We have a small, but mighty faculty, and our Ph.D. admission process is deliberately geared towards recruiting a small, but mighty group of Ph.D. students. We limit the number of Ph.D. students admitted to ensure each Ph.D. student fits with the research interests of our department and is provided mentoring and funding.
  2. We are in this together. Research in my lab is a collaborative process.  This means my graduate and undergraduate students and I are putting our heads collectively together to generate new knowledge and create new models and methods.  We work on the research together.  I meet with Ph.D. students at least once a week and spend many additional hours reading, editing, and writing journal papers with my students.
  3. It’s a disruptive time to be in supply chain design. As the introduction to this post illustrates, its a disruptive time to be in supply chain design.  My hypothesis is that supply chains of today are optimized for yesterday’s customers.  This means the world needs more creative ideas and needs to utilize the massive amounts of data being generated today to drive decision making.  Thus, the research we are doing is important and has the potential to improve efficiency of commercial and nonprofit organizations.  To learn more, check out my RED (Research, Education and Discovery) Talkthe Data Promise” (where I describe research on data in supply chains starting at 7:50), a webinar where I describe on-demand warehousing and logistics, and this interview about on-demand logistics .
  4. Low boundaries to collaboration across campus. My students and my research have benefited greatly from the insights of RPI’s helpful faculty members, both in the ISE department and beyond. Ph.D. students are encouraged to take courses across disciplines (e.g., Ph.D. students take data analytics from IDEA, optimization theory from mathematics, machine learning, data mining, and algorithms classes from computer science, transportation and econometric modeling from Civil Engineering, queuing from Electrical Engineering, data analytics from ITWS, sourcing from Lally business school, and decision making from cognitive science departments).

 

Applicants are encouraged to apply to Rensselaer’s Decision Sciences and Engineering Systems Ph.D. program, housed in the Industrial and Systems Engineering Department.  Please indicate in your statement of purpose, your interest to work with me.  If you currently reside in the US, we sponsor trips to have top accepted PhD students visit the campus, meet with faculty, and see the area.  Students in my research lab are funded, either via research assistantships, teaching assistantships, or fellowships.  Additional funding and scholarships are available for talented domestic applications.

If interested, please apply by January 2nd, 2018.   Note, applications are reviewed beyond the deadline, so apply even if you miss the January 2nd deadline.  Admission decisions are made by a committee and the final decision resides with the graduate school (outside of our department).

Please reach out to me via email (pazouj@rpi.edu) if you have any questions.  Tell your friends, co-workers, former students, current students, etc.  Thanks! Jen

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On-Demand Warehouses

Check out the latest WERC Sheet for a nice write-up about on-demand warehouses.

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My research team and I are rethinking supply chain design.  We are exploring creative solutions around on-demand warehousing and crowdsourced deliveries, in which marketplaces provide access to resources (when and where they are needed), rather than owning them.  This creates a dynamic supply network, able to respond to changing demand requirements.  But, such systems are inherently more complex than traditional systems.  To address these challenges, we are working on new network design models to capture on-demand business models (for a quick overview,  check out Flexe’s videos ) and will use these models to quantity the benefit in terms of access to scale, reduced commitment granularity, and reduced capacity granularity.  We are also conducting basic research on how best to provide a set of decentralized users choice to entice them to provide access to their resources.

Blockchain Technology – Guest Blog Post

blockchain

Happy (almost) End of the Semester.  I am happy to share a guest blog post by two undergraduate researchers, Mara and Jake, about their adventures into blockchain technology.

I’m hoping to get more undergraduate students blogging about their research interests, and so added them under the people heading.  Click here for Mara and Jake’s blog post about blockchain technology for supply chain applications.

I’m super excited about this technology and think it has great potential in supply chains.  Specifically, I believe supply chains and logistics are becoming more democratized, which results in a need for decentralized and distributed decision making.  Another area of my research has been in improving supply chain visibility.  In theory, visibility should be solved by now, but I have a number of data points that show in practice it isn’t.  My hypothesis for this discrepancy is that a top-down approach to visibility is hard to achieve in practice.  This is because to have visibility into your supply chain requires decentralized entities to agree to connect data bases and systems, share data, etc., and this is a challenging management and technology problem.  One promising technology to improve visibility is blockchain technology, which uses decentralized protocols capturing and validating information transactions between multiple users via a distributed ledger system.  My hope is to report more on this research in future posts.

IIE Transactions Best Paper Honorable Mention

 

ISERC 2016 Repositioning Rental Vehicles Presentation

My co-authors and I received an honorable mention designation in the IIE Transactions Focused Issue on Design and Manufacturing Best Applications Paper Award Competition for 2016. (The award is selected by an examining committee from all papers published from July 1, 2014 through June 30, 2015, issues 46:7 through 47:6).

Roy, Debjit, Jennifer A. Pazour, and René De Koster. “A novel approach for designing rental vehicle repositioning strategies.” IIE Transactions 46.9 (2014): 948-967.

While the paper can be downloaded here  I also had the opportunity to present our research at the Industrial and Systems Engineering Research Conference.  If you weren’t able to attend my talk, here’s the cliff notes version.

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The rental car industry has experienced “the Amazon effect” where customers place requests with little or no warning.

ResearchFocus

An important tactical decision for vehicle rental providers is the design of a repositioning strategy to balance vehicle utilization with customer wait times due to vehicle unavailabilities.

 

RentalOptions

To address this problem, this article analyzes alternative repositioning strategies: a no-repositioning strategy, a customer repositioning strategy, and a vehicle repositioning strategy, using queuing network models that are able to handle stochastic demand and vehicle unavailabilities.

ResearchGoal

Optimization models are formulated to determine the repositioning fractions for alternate strategies that minimize the rental provider’s cost by balancing repositioning costs with customer waiting penalty costs. The nonlinear optimization problems are challenging to solve because the objective functions are non-differentiable and the decision variables (such as effective arrival rates and customer repositioning fractions) are interrelated.

CostFunctions

Therefore, a two-phase sequential solution approach to estimate the repositioning fractions is developed. Phase 1 determines the effective arrival rates by developing an approximate network model, deriving structural results, determining a high-quality solution point, and refining the solution. Phase 2 determines the repositioning fractions by solving a transportation problem.

SolutionApproach

Numerical experiments are used to evaluate the efficacy of the proposed solution approach, to analyze alternate repositioning strategies, and to illustrate how the developed techniques can be adopted to create a better readiness at a depot.

CurrentState

OrlandoExample

Conclusions

2015 End-of-Year Update

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Art done on my whiteboard by my talented brother-in-law Blake Neubert.

The red ink from grading exams combined with the still-green grass on campus has me in the holiday spirit.  Here’s my blog tradition of an end-of-year update.

The biggest update from 2015 was a change in location.  I made the move to Rensselaer Polytechnic Institute this summer and it has proved to be a Pareto-optimal life solution.  The Industrial and Systems Engineering department at RPI is a nice place to be a junior faculty.  Already, interactions with my colleagues have led to new insights and directions for my research, and mentoring has led to a potential industry project and an award nomination.  We love our new community in Troy, and my husband found a super-charged job as a data analyst for Vicarious Visions.

In 2015, I have been lucky to lead a talented research team that has helped further research on the development of mathematical representations of complex systems and processes to better understand the implications of their design and operation.  My research has focused on three main stems of discovery: military logistics, distribution systems, and peer-to-peer sharing systems.  In 2015, I received my first NSF funding.  The project focuses on peer-to-peer sharing systems, which are systems where a resource owned by an individual is collectively shared with a group of users. The shared resource can be a physical resource (like a power drill) or a human resource (like the ability to perform a task). By focusing on access over ownership, these Systems allow physical assets to be consumed as services and tasks to be completed by independent individuals. Examples include sharing economy companies like Uber, Flexe, Cargomatic, and Instacart.

I’m thankful that I was able to convince Shahab Mofidi to transfer with me from UCF to RPI.  He is working on his Ph.D. research on two-stage multi-product procurement decisions with cost fluctuations.  He did an excellent job presenting his work at ISERC (to 3 generations of his academic family) and INFORMS.  It’s fun to jointly put our heads together during our weekly research meetings.

4Generations

Shahab Mofidi presents to three-generations of his academic tree at the 2015 ISERC conference (Mofidi, Pazour, Meller, [Bozer, not pictured], White)

I started working with Uzma Mushtaque this summer, and she has jumped right into her research on developing and using models that incorporate assortment properties into random utility models.  Specifically, she is interested in how to explicitly model no-choice probabilities associated when individual users are recommended an assortment of options to choose from.  Her work has wide application from recommendations in e-commerce and Netflix, as well as facilitating freelancer options in peer-to-peer resource sharing apps.  Shahab and she gained valuable experience attending the Purdue CIBER PhD Consortium on International Operations Management.  Uzma is excited to have her first research abstract accepted to present at ISERC in 2016.  Finally, I am excited to have Yuan (Eric) Meng join my group.  He will research bi-level optimization models for peer-to-peer sharing systems.

As new members joined, a number of students graduated in 2015.  Patrick Reilly defended his Master’s Thesis this spring on “Propagation of Unit Location Uncertainty in Dense Storage Environments”.  With help from Dr. Kellie Schneider, a journal out of his work has been submitted for review.  Mohamed Awwad defended his Ph.D. dissertation this Fall, which focuses on searching in dense storage environments.  We have received constructive reviews back on a submitted paper and are currently working on revisions.  Finally, Faraz Ramtin (who was the first student to jointly work with me) graduated this Spring with his Ph.D. His work on MIAPP AS/RS is ongoing and has led to interesting discussions with other facility logistics researchers who are modeling other aspects of the technology used for distribution.  He has two accepted publications in IIE Transactions and is preparing a third contribution for publication.

 

MohamedDefense

Mohamed Awwad defends his dissertation at UCF, while I attend proudly from NY.

Undergraduate researchers bring a rad perspective to our research.  This semester I had six undergraduates who worked on projects associated with supply chain modeling of ship-from-store fulfillment, sharing economy models for supply chains, and seabased logistics.

On my drive from Florida to New York, I got an awesome tour of Duke’s campus from Catherine Ninah, who was an undergraduate researcher at UCF and conducted research via an REU.  Catherine Ninah and Kristin Elias were involved with ICubed at UCF – their collaborations with art students created some cool art based on our seabased logistics research.

 

In 2015, I finally got to teach a logistics course in the spring, and enjoyed incorporating my research and the material handling and logistics US roadmap into the course.  I just wrapped up a rewarding class on the Design and Analysis of Supply Chains.  One of the introductory assignments was to have students create a “Supply Chain and You” slide to motivate the students to think about the importance and impact of the course topics on the students’ lives, and also allowed me to get to know the students better.   Here’s mine:

Supply Chains and Me

The course ended with a review of the topics helped by students’ memes.  Here is my favorite, which reminds students when calculating the amount of safety stock you need to use the square root of the lead time.

Final Exam Review - Fall 2015

My mission to create more Industrial Engineers has continued in 2015.  I enjoyed participating at CAMP Connect, presenting to the Eureka! Program of Girls Incorporated in the Capital Region, to the RPI student chapter of IIE about “What is Industrial Engineering and Why Does it Rock?” and attending the Women at Rensselaer Mentor Program.

IMG_2017

Attending the Women at Rensselaer Mentor Program.

My 2016 calendar already contains a number of projects that will allow me to learn a lot.  Some I am most excited about include an interdisciplinary academic-industry partnership proposal on smart, secure on-demand authorization systems for logistics and distribution  (with material scientists and computer science researchers from SDSMT), presenting at the Transportation Research-Board workshop on “On-Demand and Sharing Economy for Freight” and leading a panel discussion at the Warehousing Education and Research Council (WERC) on Crowdsourcing and Collaborative Warehousing and Logistics.

Cheers!

Jen

Successful Defenses

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Congrats to Dr. Faraz Ramtin, who successfully defended his Ph.D. dissertation thesis entitled, “Modeling and Analysis of Automated Storage and Retrieval Systems with Multiple in-the-aisle Pick Positions,” and to Patrick Reilly, who successfully defended his M.S. thesis entitle, “Propagation of Unit Location Uncertainty in Dense Storage Environments.”

I am super proud of both students, who are excellent researchers and human beings.

 

 

Faraz’s dissertation consists of three contributions all focusing on a special type of case-level order fulfillment technology – an “Automated Storage and Retrieval System with Multiple in-the-aisle pick positions.” These semi-automated systems are common in temperature-controlled warehouses.  Our first contribution includes the first study to analyze AS/RS with multiple in-the-aisle outputs. We develop expected travel time models for random storage policies and provide design insights into these systems.  In our second contribution, we considered the use of MIAPP-AS/RS to fulfill orders for non-identical items’ demand, which relaxed some of the assumptions we made in the first contribution. Specifically, we focused on an important practical design decision, the optimal SKU assignment problem. We studied the impact of different pick position assignments on system throughput, as well as system design trade-offs that occur when the system is running under different operating policies and different demand profiles. We developed optimization models to find the optimal assignment that minimizes the expected travel time.  Finally, we developed optimization models for the SKU-to-pick position assignment problem for dedicated and class-based storage policy for MIAPP-AS/RS.  By exploiting the structure of these optimization models, we decomposes the problem using Benders decomposition.

IMG_1722

The first two contributions of Faraz’s dissertation work has been accepted for publication:

  • Ramtin F., Pazour J. A. “Analytical Models for an Automated Storage and Retrieval System with Multiple in-the-Aisle Pick Positions”. IIE Transactions, 46(9), 968-986.
  • Ramtin F., Pazour J. A. “Product Allocation Problem for an AS/RS with Multiple in-the-Aisle Pick Positions”. IIE Transactions, Accepted Manuscript.

He is working on the manuscript of his third contribution, which explores a dedicated storage policy in these systems.

Patrick’s work focuses on dense storage environments and adds an additional dimension to the warehousing literature in that area, specifically item location uncertainty.  Effective space utilization is an important consideration in logistics systems and is especially important in dense storage environments. Dense storage systems provide high-space utilization; however, because not all items are immediately accessible, storage and retrieval operations often require shifting of other stored items in order to access the desired item, which results in item location uncertainty when asset tracking is insufficient. Given an initial certainty in item location, we use Markovian principles to quantify the growth of uncertainty as a function of retrieval requests and discover that the steady state probability distribution for any communicating class of storage locations approaches uniform. Using this result, an expected search time model is developed and applied to the systems analyzed. We also develop metrics that quantify and characterize uncertainty in item location to aid in understanding the nature of that uncertainty. By incorporating uncertainty into our logistics model and conducting numerical experiments, we gain valuable insights into the uncertainty problem such as the benefit of multiple item copies in reducing expected search time and the varied response to different retrieval policies in otherwise identical systems.IMG_1745

2014 in Review

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To keep up with my blogging traditions, below you will find my list of highlights from this past calendar year.

  1.  My academic family grew. Ali Bozorgi, who was co-advised by Dima Nazzal and myself, become the first branch on my academic tree. Ali is currently a postdoctoral fellow at Clemson University and Greenville Health System.  My academic family tree should add two more branches in May when Faraz Ramtin will defend his Ph.D. dissertation and Patrick Reilly will defend his master’s thesis.
  2. Modeling is powerful stuff. My team and I spent lots of time and brain power developing models to quantify and evaluate sea-based logistics system design in the face of imperfect visibility.  We got great feedback when we presented this work to the Marines and the Navy in May, as well as hosted our Office of Naval Research managers in our lab in November.  I am proud of this work as it is illustrative of how mathematical models can be extremely powerful tools in understanding complex problems, and testing possible solutions.  I find research that builds mathematical models and uses them as a playground to test hypothesis and to gain understanding and insights into complex problems is rewarding and has impact.
  3. School is cool.  Education and learning continue to be cool and rewarding experiences for me.  I greatly enjoy my time in the classroom, having taught a graduate production and inventory control course, a graduate operations research course, and an undergraduate industrial engineering in the service sector course this past year.
  4. Conferences are good for my soul. I always look forward to professional conferences, but this year in particular I found conferences to be extremely valuable.  They allowed me to see my research from the forest rather than the trees, and I got to spend time in fun places with new and old friends.
  5. Fruitful and fun collaborations.  Such collaborations with colleagues and students resulted in a number of publications being accepted this year.
    1. Bozorgi, Ali, Pazour, Jennifer A., and Nazzal, Dima, 2014, “A New Inventory Model for Cold Items that Considers Costs and Emissions,” International Journal of Production Economics, 155, 114–125. (Special Issue: Celebrating a Century of the Economic Order Quantity Model).
    2. Carrano, Andres, Pazour, Jennifer A., Roy, Debjit, and Thorn, Brian, (to appear) “Selection of Pallet Management Strategies based on Carbon Emissions Impact,” International Journal of Production Economics. (Special Issue: Carbon-efficient Production, Supply Chains and Logistics).
    3. Pazour, Jennifer A., and Carlo, Hector J. (to appear) “Warehouse Reshuffling: Insights and Optimization,” Transportation Research Part E.
    4. Pazour, Jennifer A. and Roy, Debjit, (to appear) “Analyzing Rental Vehicle Threshold Policies that Consider Expected Waiting Times for Two Customer Classes,”‘ Computers & Industrial Engineering.

All in all, life was pretty great in 2014.  I’m looking forward to what’s in store in 2015!