Researchers created a mathematical model that helps transplant centers make decisions about when to move forward with a matching donor and when to wait. This work can potentially help decision making in other industries. Photo via Getty Images

To wait, or not to wait? That is the question — or at least it might be, if you need a kidney transplant.

Nearly 89,000 Americans with chronic kidney disease are on a waitlist for a new organ, and an estimated 13 people die each day while awaiting a transplant. But there are real costs to matching patients with the first donor that becomes available, just as there are equally real costs to having them wait in hopes of finding a better one.

Recently, Rice Business professor Süleyman Kerimov and colleagues at Stanford University and Northwestern University developed a mathematical model that helps clarify when it's best to match patients to donors as quickly as possible and when it's best to wait.

Their findings, which appear in two papers published in Management Science and Operations Research, respectively, could help optimize all manner of matching markets in which participants seek to connect with potential partners based on mutual compatibility — a sprawling category that encompasses everything from e-commerce platforms to labor markets that match employees with employers.

Kerimov and his colleagues focused on programs that match live kidney donors with people who need transplants. Live donors typically volunteer to give one of their kidneys to a loved one. But biological differences between a donor and their intended recipient can render the pair incompatible.

Kidney exchange programs solve this problem by swapping donors amongst different patient-donor pairs, choreographing a kind of kidney-transplant square dance aimed at finding a compatible partner for every willing donor.

In countries such as Canada and the Netherlands, kidney-matching programs perform a batch of matches every few months (called periodic policies). American programs, meanwhile, tend to perform daily matches (called greedy policies). Both models seek to produce the greatest number of high-quality transplants possible, but they each have advantages and disadvantages.

Less frequent matches in a periodic policy allow more patient-donor pairs to accumulate in the kidney exchange network, creating potential for better matches over time. But this approach risks making some patients sicker as they wait for a better match that might never appear.

Arranging feasible matches as soon as they become available in a greedy policy avoids that predicament. But it means passing up the opportunity to make a potentially better match that could represent the possibility of a longer, healthier life.

Balancing these trade-offs is tricky. There is no way of predicting precisely when a patient-donor pair with a particular set of characteristics will show up at the kidney-exchange network. And in the world of organ transplants, there are no do-overs.

Kerimov and his colleagues have constructed a mathematical model that represents a simplified version of a kidney exchange network.

Within the model, the researchers could dictate which patient-donor pairs could be matched with one another. They can also assign different values to individual matches based on the number of life years they provide. And they can establish the probability that various kinds of patient-donor pairs with particular characteristics might arrive at the network and queue up for a transplant at any given time.

Having set those parameters, the researchers applied different matching policies and compared the results. As it turns out, the answer to whether one should wait or not is: It depends.

To determine which policies generated the best outcomes — i.e., performing matches either daily or periodically — the researchers calculated the difference between the total value in life years that could possibly be generated within the network and the amount generated by a specific policy at a particular point in time. The goal was to keep that number, evocatively dubbed "all-time regret," as small as possible over both the short and long term.

In their first paper, Kerimov and his team explored a complex network in which donor kidneys could be swapped amongst three or more patient-donor pairs. When such multiway matches were possible, the cost of applying a daily-match policy turned out to be onerous. Using all available matches as quickly as possible eliminated the chance of later performing potentially higher-value matches.

Instead, the researchers found they could minimize regret by applying a periodic policy that required waiting for a certain number of patient-donor pairs to arrive before attempting to match them. The model even allowed the team to calculate precisely how long to wait between matchmaking sessions to get the best possible results.

In their second paper, however, the team looked at a simpler network in which kidneys could only be swapped between two donor-patient pairs. Here, their findings contradicted the first: Applying a daily-match policy minimized regret; a periodic matching process yielded no benefit whatsoever.

To their surprise, the researchers discovered they could design a foolproof algorithm for making two-way matches in simple networks. The algorithm employed a ranked list of possible match types; and the researchers found that no matter how many patient-donor pairs of various kinds randomly arrived at the network, the best choice was always simply to perform the highest-ranked match on the list.

In future research, Kerimov hopes to refine the model by feeding it data on real patient-donor pairs that have participated in actual kidney exchange programs. This would allow him to create a more realistic network, more accurately calculate the likelihood that particular kinds of patient-donor pairs will show up, and assign values to matches based not only on life years but also on rarity and difficulty. (Certain blood types and antibody profiles, for example, are rarer or more difficult to match than others.)

But Kerimov already suspects that in a real-world situation, the wisest course of action will be to alternate between periodic and greedy policies as circumstances dictate. In a simple region within a kidney exchange network that only allows for two-way matches, pursuing a greedy policy that involves taking the first match that appears on a fixed menu of options would be the best choice. In a more complex region that allows three-way matches, however, pursuing a periodic matching policy that involves waiting to make rarer and more difficult matches would ultimately offer more patients more years of healthy life.

The benefits of choosing flexibly between greedy and periodic policies should hold for any kind of matching market that can be represented by a network with simpler and more complex regions, such as a logistics system that matches online orders to delivery trucks or a carpooling system that matches passengers with drivers across different parts of a city.

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This article originally ran on Rice Business Wisdom and was based on research from Süleyman Kerimov, an assistant professor of management – operations management in the Jones Graduate School of Business at Rice University.

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State-of-the-art innovation hub opens in Houston Energy Corridor

flagship facility

French multinational company Schneider Electric has opened a new 10,500-square-foot, state-of-the-art Energy Innovation Center in Houston.

The new facility is located in Houston’s Energy Corridor and is designed to “foster increased collaboration and technological advancements across the entire value chain,” according to a news release from the company. The new Houston location joins Schneider's existing innovation hubs in Paris, Singapore and Bangalore.

The venue will serve as a training center for process control engineers, production superintendents, manufacturing managers, technical leads and plant operations personnel. It can simulate various real-world scenarios in refineries, combined-cycle power plants, ethylene plants, recovery boilers and chemical reactors.

It includes an interactive control room and artificial Intelligence applications that “highlight the future of industrial automation,” according to the release.

"Digitalization is significantly enhancing the global competitiveness of the U.S. through continuous innovation and increased investment into next-generation technology," Aamir Paul, Schneider Electric's President of North America Operations, said in the release.

Texas has over 4,100 Schneider Electric employees, the most among U.S. states, and has facilities in El Paso, the Dallas-Fort Worth metroplex and other areas.

"This flagship facility in the Energy Capital of the World underscores our commitment to driving the future of software-defined automation for our customers in Houston and beyond,” Paul added in the release. “With this announcement, we are excited to continue supporting the nation's ambitions around competitive, efficient and cost-effective manufacturing."

Schneider Electric says the new Houston facility is part of its expansion plans in the U.S. The company plans to invest over $700 million in its U.S. operations through 2027, which also includes an expansion at its El Paso campus.

The company also announced plans to invest in solar and battery storage systems developed, built, and operated by Houston-based ENGIE North America last year. Read more here.

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This story first appeared on our sister site, EnergyCapitalHTX.com.

9 can't-miss Houston business and innovation events for April

where to be

Two new conferences will launch while another longtime business competition celebrates its 25th anniversary this month in Houston. Plus, there are networking opportunities, family tech events and more.

Here are the Houston business and innovation events you can't miss in April and how to register. Please note: this article might be updated to add more events.

​Ion Block Party: Art Crawl

Network and socialize with other tech enthusiasts and business-minded individuals while taking in the new gallery at Community Artists’ Collective and experiencing the immersive dome at Omnispace360. See work by Joel Zika, who will showcase his digital sculptures through augmented reality screens, and other public art around the Ion while also enjoying food and drink.

This event is Thursday, April 3, from 4-7 p.m. at the Ion. Click here to register.

​CLA Presents: Raising Capital over Happy Hour

Gain a better understanding of the capital-raising process and various funding opportunities at this educational happy hour. Keith Davidson, the market leader for CLA in Dallas and former CFO of ICS, will present.

This event is Thursday, April 10, from 4-6 p.m. at The Cannon. Click here to register.

Rice Business Plan Competition 

The Rice Alliance for Technology and Entrepreneurship will host the 25th annual Rice Business Plan Competition this month. Forty-two student-led teams from around the world, including one team from Rice, will present their plans before more than 300 angel, venture capital, and corporate investors to compete for more than $1 million in prizes.

This event is April 10-12. Stream the Elevator Pitch Competition and Final Round here.

RSVF Annual Conference

The Rice Student Venture Fund will host its first-ever Annual Conference to celebrate the university's entrepreneurial spirit and the rising generation of student-led innovation. The conference will include live startup demos, an RSVF fund update, a keynote fireside chat, a builder-investor panel and networking. RSVF welcomes students, alumni, investors, faculty and staff, and innovators and community members of the broader tech scene.

This event is Monday, April 14, from 4-8 p.m. at the Ion. Click here to register.

​TEX-E Conference

TEX-E will host its inaugural conference this month under the theme "Energy & Entrepreneurship: Navigating the Future of Climate Tech." The half-day conference will feature a keynote from Artemis Energy Partners CEO Bobby Tudor as well as panels with other energy and tech leaders from NRG, Microsoft, GE Vernova and TEB Tech.

This event is Tuesday, April 15, from 1-4:30 p.m. at the Ion. Click here to register.

Houston Methodist Leadership Speaker Series 

Hear from Dr. Jonathan Rogg, Chief Quality Officer and Vice President of Operations at Houston Methodist Hospital and a a practicing emergency medicine physician, at the latest Houston Methodist Leadership Speaker Series. Rogg will present "Leadership from the Bedside to the Boardroom."

This event is on Wednesday, April 23, from 4:45-6 p.m. at the Ion. Click here to register.

Ion Family STEAM Day– Let's Build a Tripwire Alarm

STEAM on Demand will host a hands-on, family-friendly engineering lesson for young ones on the Ion Forum Stairs. Kids will learn to create and test their own working alarm system. The event is geared toward those ages 7 to 14.

This event is Sunday, April 26, from 10 a.m. to noon at the Ion. Click here to register.

 Greentown Houston Fourth Anniversary Transition On Tap

Climatetech incubator Greentown Labs will celebrate its fourth anniversary with a special edition of its signature networking event, Transition On Tap. Entrepreneurs, investors, students, and friends of climatetech are invited to attend.

This event is Tuesday, April 29, from 5:30-7:30 p.m. at Greentown Labs. Click here to register.

Integrate Space Technology Into Your Small Biz

The SBA Houston District Office and the UH Technology Bridge will host a collaborative event designed to help small businesses leverage space technology for prototype development. Attendees will also hear from industry experts on resources and gain access free technical engineering assistance to help accelerate their businesses.

This event is Wednesday, April 30, from 9:30-11:30 a.m. at UH Technology Bridge Innovation Center. Click here to reserve your spot.

Texas university's innovative 'WaterHub' will dramatically reduce usage by 40%

Sustainable Move

A major advancement in sustainability is coming to one Texas university. A new UT WaterHub at the University of Texas at Austin will be the largest facility of its kind in the U.S. and will transform how the university manages its water resources.

It's designed to work with natural processes instead of against them for water savings of an estimated 40 percent. It's slated for completion in late 2027.

The university has had an active water recovery program since the 1980s. Still, water is becoming an increasing concern in Austin. According to Texas Living Waters, a coalition of conservation groups, Texas loses enough water annually to fill Lady Bird Lake roughly 89 times over.

As Austin continues to expand and face water shortages, the region's water supply faces increased pressure. The UT WaterHub plans to address this challenge by recycling water for campus energy operations, helping preserve water resources for both the university and local communities.

The 9,600-square-foot water treatment facility will use an innovative filtration approach. To reduce reliance on expensive machinery and chemicals, the system uses plants to naturally filter water and gravity to pull it in the direction it needs to go. Used water will be gathered from a new collection point near the Darrell K Royal Texas Memorial Stadium and transported to the WaterHub, located in the heart of the engineering district. The facility's design includes a greenhouse viewable to the public, serving as an interactive learning space.

Beyond water conservation, the facility is designed to protect the university against extreme weather events like winter storms. This new initiative will create a reliable backup water supply while decreasing university water usage, and will even reduce wastewater sent to the city by up to 70 percent.

H2O Innovation, UT’s collaborator in this project, specializes in water solutions, helping organizations manage their water efficiently.

"By combining cutting-edge technology with our innovative financing approach, we’re making it easier for organizations to adopt sustainable water practices that benefit both their bottom line and the environment, paving a step forward in water positivity,” said H2O Innovation president and CEO Frédéric Dugré in a press release.

The university expects significant cost savings with this project, since it won't have to spend as much on buying water from the city or paying fees to dispose of used water. Over the next several years, this could add up to millions of dollars.

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A version of this story originally appeared on our sister site, CultureMap Austin.