Board of Directors

Martin Handwerker, President

After studying at Cornell University and receiving Bachelors and Masters degrees in Computer Science, Martin married and moved to Silicon Valley where he has lived for 18 years. He worked at software companies specializing in speech synthesis, customer relationship management, and streaming databases. He lead a team at Microsoft responsible for designing the backing storage system for OneDrive, managed a team of developers responsible for the user visible parts of, and most recently is leading a machine learning team at Google responsible for selecting which ads are displayed on mobile devices. He is a father of SPHDS students in the sixth and eighth grades, and an SPHDS graduate now at Jewish Community High School of the Bay.

Linor Eylon, Vice President

Linor is passionate about Jewish day school education and has devoted 20 years to working with Jewish children. From synagogue youth director in Encinitas, California, to preschool teacher and director in Tacoma, Washington, to preschool founder in Olympia, Washington, and finally to Sunnyvale where, for 10 years, Linor taught and directed in South Peninsula Hebrew Day School’s Gan Aviv. Linor graduated, Summa Cum Laude, from San Diego State University with a B.S. in Child and Family Development. For her teaching at SPHDS, Linor was the recipient of the prestigious Grinspoon-Steinhardt Award which honors outstanding Jewish educators throughout North America. Linor along with her husband, Eyran, and their 3 children have lived in Sunnyvale for the past 14 years. Linor and Eyran are proud former SPHDS parents where all 3 children are alumni of the school and have since moved on to Kehillah Jewish High School, the Israel Defense Forces and college.

Ari Tuchman, Treasurer

Ari is co-founder and CEO of Quantifind. a predictive analytics company. He received his doctorate in atomic physics from Yale University focusing on Bose Einstein condensation. Ari is the father of Danelle, Natalia, Adin and Nurielle and is married to Liora Schultz. He also gives a women’s advanced talmud shiur in the community.

Eran Leib, Secretary

Eran Leib grew up in Israel where he served as an officer in Mamram (IDF), married Orit and co-founded Whitebox Security. In 2015, SailPoint Tecnologies acquired Whitebox and the Leib family moved to Silicon Valley. He is a father of four, three of which are SPHDS students in kindergarten and grades two and five. His education included Bnei Akiva middle school mechina, Bar Ilan University High School and a BS in Computer Science from Tel Aviv Academic College.

Nissa Johanix, Past President

Nissa Johanix is the mother of Elazar (entering Second grade) and Amichai (Kindergarten) at SPHDS. She served on the SPHDS Board from 2009-2012. She is an alumni of SPHDS, having attended grades K-8. During college, she ran the SPHDS B’nei Akiva after-school program and worked in the SPHDS office. Currently Nissa is serving as a member of the Search Committee for the Executive Director, Principal and Early Childhood Education Director. Outside SPHDS, Nissa is active with several Bay Area Jewish organizations including AIPAC, Jewish Federation of Silicon Valley, Jewish Community Federation of San Francisco, Congregation Kol Emeth, and The Friendship Circle. With her many years of active participation in the affiliated Jewish community of Silicon Valley, Nissa has developed relationships with key leaders from a wide variety of Jewish institutions and has experience navigating the nuances of our community. In addition to her volunteer roles, Nissa is trained as a birth and postpartum doula, and is passionate about yoga and cooking. Nissa’s husband, Tom, works for a tech start-up, and volunteers with several Jewish organizations.

Maury Alcheck, Director

Barry Berkowitz, Director

Barry works for Google and has been an active member of the Jewish community. He is on the Board of Meira Academy, has served on the board of directors as the Treasurer of Congregation Emek Beracha for several years, and was a former Board Member of NCSY on Long Island, NY. Barry's son Jason is in Kindergarten at SPHDS. Barry lives in Palo Alto with his wife Erica and their three adorable children.

Adinah Katz, Director

Adinah Katz received 16 years of formal Jewish education, 15 years of which took place in the Jewish Day School system of South Florida. After graduating from Columbia University with a major of Mathematics & Economics and another major of Jewish Studies, she moved to Boston and worked in tech. She was active in both the Young Israel of Brookline and the Chabad Chai Center of Brookline. Five years ago she moved to the Bay Area and regularly attends Emek Beracha.  She currently works at Facebook where she analyzes big data in order to rid Instagram of malicious users and bad content. Adinah is passionate about the importance of Jewish education and is proud to serve on the SPHDS Board.

Ian Prager, Director

Ian Prager is a Director at the investment banking firm Prager & Co., LLC and runs the Firm’s quantitative group.  In addition to leading the analytics team, Ian provides quantitative and strategic support for many of Prager's public and private higher education clients in the United States and Canada.  His experience includes designing liability management policies, strategic debt management analytics, central bank design, implementation and operation, interest rate derivative policies and analytics, swap portfolio strategies, credit analyses and strategic planning.  Before joining Prager, Ian spent seven years working for Lockheed Martin in their Space Systems Division in numerous capacities. Ian's tenure at Lockheed began in the Reliability Group focusing on statistics and probability.  He moved into Mission Design and Orbit Determination shortly after joining Lockheed and completed his tenure working in research and development in the guidance, navigation and control group.  Ian received his Bachelor of Arts from Claremont McKenna College in Mathematics and Economics and his Masters of Science from Stanford University in Aeronautical and Astronautical Engineering.

Bonnie Rosenberg, Director

Bonnie Rosenberg is an aluma of SPHDS.  She received a B.S. in Chemistry from Stanford University and an M.D. from the UCLA School of Medicine.  She is a graduate of the UCSF residency program in Internal Medicine.  She remained on at UCSF as a faculty member,  teaching medical residents and caring for patients.  In 2002,  she left UCSF to establish her own private practice where she devotes her time exclusively to caring for patients.  Her private practice is located in Menlo Park.  She lives with her husband and two teenage children in Palo Alto.

Esther Rosenfeld, Director

Esther is a strong proponent of the importance of Jewish day schools in promoting and preserving Jewish identity. She grew up in New York, where she attended Solomon Schechter day school and Hebrew Academy of Nassau County, and her daughters have attended/are attending SPHDS, Yavneh and Kehillah Jewish high school locally. Esther is an attorney who has been practicing family law in San Mateo and Santa Clara counties for about 15 years, earning accolades for excellence in practice. Esther and her husband Shachar, an accountant, are almost a Jewish joke: they missed the "doctor" part.

Dr. Liza Shiff, Director

Liza is the mother of two current SPHDS students. As a Los Altos native, she and her family have strong ties to the community; her parents served on the SPHDS board many years ago and she and her brothers are graduates of SPHDS. She has been very involved in school volunteer work, currently serving on the walkathon committee and as a grade 2 room parent. She is a physician and has contributed to the medical profession in numerous capacities, including previous service as local president of the American Medical Women’s Association and serving on the executive council of the Santa Clara County Medical Association.