board & advisors


Phase Change Board of Directors

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Mark Bieler
Mark Bieler has been a Phase Change board member since June 2009.

He is the president of Mark Bieler Associates Inc., a management consulting firm for private and public sector organizations on strategic human resources and organization development. His clients have included The Westfield Group, Morgan Stanley Retail, Ogilvy & Mather, Mercantile Trust, and the CIA.

Mark is also chairman of the Edwin Gould Foundation, an incubator for social entrepreneurs and their education initiatives.

Previously, he was director of human resources for Bankers Trust Company, and executive vice president of the parent organization, Bankers Trust Corp. He had human resources responsibilities for the Banking Operations Group and the international, U.S., and world corporate banking units.



Steve Bucuvalas
Steve Bucuvalas founded Phase Change in 2005. He is the CEO and a board member.

Steve started the company following several years of research in combining formal methods, computational mathematics, and semantic technologies for use in business applications.

Steve's personal engineering experience includes developing one of New England's first ATM systems in mainframe assembly language and Prolog-based productivity tools for business analysts.

He served as the Bank of New England's technology senior vice president, Prudential Home Mortgage's vice president of advanced technology and architecture, and Nexstar Financial Corp.'s chief technology officer.

In 1996, Steve founded eoTek LLC to develop internet-based software solutions for mortgage, financial services, and communications companies. eoTek's clients included Chase Mortgage, Banc One, and MCI/WorldCom. The company grew to approximately 80 employees and contractors before it was sold to Nexstar Financial Corp. in 2000.


Jeffrey Diggins
Jeffrey Diggins has been on the Phase Change Board of Directors since 2018. He was previously on the Board of Advisors.

He is an officer and Board Member for Tactical Communications Group LLC, a spin-off from Dynamics Research Corp., and a leader in the customizable data link S/W business supporting our military and more than 24 countries around the world.

Jeffrey has over 20 years of banking and business-turnaround experience and managed over $3.5 billion of commercial and industry loans, private equity and leveraged financing with Bank of America and Endurance Capital. He also led Precix through a transitional turnaround that resulted in the company's sale to ZD USA Holdings Inc.

He obtained both his Bachelor of Science in Economics and his MBA from Texas A&M University. Jeffrey has served on more than 12 corporate boards and supports numerous non-profit entities, including founding the Yarmouth Education Foundation.

Gary Brach
Gary Brach has been the president of Phase Change since October 2016, and a board member since April 2016. He is focused on introducing Phase Change to the market.

His background is in the software industry with over 25 years of experience primarily as a software entrepreneur in the storage and insurance industries.

He was formerly a director at Intuit Inc. after selling Prestwick Services LLC, the leading premium pay-as-you-go billing platform, to Intuit in 2013.

Before joining Prestwick, Gary was the CEO of AgencyPort Software, the leading provider of agent portal technology for the property and casualty insurance industry. AgencyPort was acquired by The Sword Group in 2009 and is now owned by Accenture Inc.

He was the co-founder and president of Smart Storage Inc., the first company to commercialize CD-Recording and archival storage virtualization software. Smart Storage was sold to OTG Software in 2001 and is now part of Dell Inc.

Howard Culang
Howard Culang has been a Phase Change board member since July 2008.

He served as president of Laurel Corp., a financial services firm, from January 1996 through December 2011. He was a managing member of JH Capital Management LLC, a private equity fund management company, from July 1998 to December 2010, and Cognitive Capital Management LLC, a management company for a fund of hedge funds, from April 2001 to December 2005.

In the past, he served as vice chairman of Residential Services Corp. of America, the holding company for Prudential Home Mortgage, Lender's Service Inc,. and Prudential Real Estate Affiliates.

Howard was also a managing director and Executive Committee-member of the Prudential Home Mortgage Company, where he worked from November 1985 to December 2005.

He once held a number of senior management positions with Citibank, NA, including senior credit officer, and served as a member of the Smart Storage Inc. Board of Directors until it was acquired by OTG Software in 2001. Howard has been a director of Radian Group Inc. since June 1999, where he serves as chairman of the Credit Committee.

Don Peskin
Don Peskin has been a Phase Change board member since November 2007.

He has more than 25 years of Wall Street and investment experience, most notably, as a managing director and principal at Donaldson, Lufkin & Jenrette, which he left in September 1997 to pursue private investment opportunities in finance, technology, and related industries. He is the founder and president of Short Hills Capital LLC, a privately held investment company.

In addition to his principal investment activities, Don is also a managing member of Chatham Hills Development LLC, a real-estate development firm, and recently served as a managing member of Cognitive Capital Management, which was the General Partner of the Cognitive Strategic Fund, a hedge fund of funds.

He also served as a member of the Ballard Petroleum LLC Board of Directors from 1997 to 2001, when the company was acquired by Alberta Energy Corp.

Don was previously a member of the Entrepreneurship@Cornell Advisory Council.

 “We cannot solve our problems with the
same thinking we used when we created them."

Albert Einstein

Phase Change Board of Advisors

John K. Thompson
John K. Thompson has been on the Phase Change Board of Advisors since 2017.

He is a principal with Marketing Science LLC, which helps start-up organizations launch and grow rapidly, and works with established companies to design, develop and launch new products and services. John is an international technology consultant with over 30 years of experience in building and growing technology companies.

Prior to founding Marketing Science LLC, John lead Dell Software Group's advanced analytics business unit (now part of Quest Software Inc.) as the executive director and general manager. He is also the co-author of Analytics: How to Win with Intelligence.

John has built start-up organizations from the ground up and he has reengineered business units of Fortune 500 firms to reach their potential. He obtained his Bachelor of Science in Computer Science from Ferris State University and his MBA in Marketing from DePaul University.

Steve Yatko
Steve Yatko has been on the Phase Change Board of Advisors since 2017.

He is the founder and CEO of Oktay Technology, a boutique consulting firm for large-scale financial and analytic trading systems. Steve has over 20 years of experience with advanced enterprise IT systems and technology.

Before founding Oktay, Steve led mission-critical development initiatives at Credit Suisse as managing director and global head of IT Research & Development, head of global core technologies, and CTO of Mission Critical Systems. He cofounded DynamicOps, a Credit Suisse spinout that provided cloud automation solutions. DynamicOps was acquired by VMWare in 2012.

Steve is also an industry advisor at Starr Investment Holdings, a multi-billion dollar New York-based investment adviser; chief technology advisor at Care Finder Total Care, cofounder of AcordIQ, and founder of Renascence Development.

Paul Walker
Paul Walker has been on the Phase Change Board of Advisors since 2017.

He is a Brooklyn-based technologist and philanthropist. Paul retired as a partner from Goldman Sachs in 2015, where he co-headed the firm’s technology division and held roles in risk management and technology. He now advises companies and investors in artificial intelligence (AI) and FinTech, a umbrella term used to describe technologies and companies that apply tech innovations to the banking and investment industries.

Paul spends his philanthropic energies working with organizations that provide opportunity and social capital to young adults through access to education, science, and critical reasoning guidance. He holds a Ph.D. in Physics from the University of Illinois and a B.A. in Physics from Cornell University.


Melvin A. Yellin
Melvin Yellin has been on the Phase Change Board of Advisors since 2017. Previously, he was a member of the Board of Directors.

He is currently president of Stone Point Corp., which provides business and financial consulting services and is actively involved in various venture capital investment opportunities. Melvin was previously a partner at Tandem Global Partners, a globally focused money management company that offers traditional and alternative investment services to sophisticated institutions. He spent the bulk of his career at Bankers Trust Company, where he was a partner, executive vice president and general counsel when it merged with Deutsche Bank in June 1999.

During his career, he acted as chairman and speaker for numerous business organization programs, including those run by the Conference Board, National Association of Corporate Directors (NACD), Columbia University Business School, and University of Wisconsin School of Business.