Question: The military self-defense system developed for the IDF was derived from the street-fighting experience of a Hungarian-Israeli who was known as what?

Context paragraphs:
Modern Arnis: Modern Arnis is the system of Filipino fighting arts founded by Remy Presas as a self-defense system.  His goal was to create an injury-free training method as well as an effective self-defense system in order to preserve the older Arnis systems.  The term "Modern Arnis" was used by Remy Presas' younger brother Ernesto Presas to describe his style of Filipino martial arts; since 1999 Ernesto Presas has called his system Kombatan.  It is derived principally from the traditional Presas family style of the Bolo (machete) and the stick-dueling art of Balintawak Eskrima, with influences from other Filipino and Japanese martial arts.

Indonesian Presidential Aircraft: The Indonesian Presidential Aircraft (Indonesian: "Pesawat Kepresidenan Indonesia" ), also known as Indonesia One with a serial number A-001 is the presidential aircraft carrying the president and vice president of Indonesia.  The aircraft was designed to meet the specific safety and security standards to support the VVIP air transportation needs of the Indonesian president, and includes a high-end self-defense system.

Sanshou: Sanshou (Wushu Sanshou), also known as Sanda (Wushu Sanda), Chinese boxing or Chinese kickboxing, is a Chinese self-defense system and combat sport.  Wushu Sanshou is a martial art which was originally developed by the Chinese military based upon the study and practices of traditional Kung fu and modern combat fighting techniques; it combines full-contact kickboxing, which includes close range and rapid successive punches and kicks, with wrestling, takedowns, throws, sweeps, kick catches, and in some competitions, even elbow and knee strikes.

Krav Maga: Krav Maga ( ; Hebrew: קְרַב מַגָּע‎ ] , "lit."  "contact-combat") is a military self-defense system developed for the Israel Defense Forces (IDF) and Israeli security forces (Shin Bet and Mossad) that consists of a combination of techniques sourced from Boxing, Wrestling, Aikido, Judo, Karate along with realistic fight training.  Krav Maga is known for its focus on real-world situations and its extreme efficiency and brutal counter-attacks.  It was derived from the street-fighting experience of Hungarian-Israeli martial artist Imi Lichtenfeld, who made use of his training as a boxer and wrestler as a means of defending the Jewish quarter against fascist groups in Bratislava, Czechoslovakia in the mid-to-late 1930s.  In the late 1940s, following his migration to Israel, he began to provide lessons on combat training to what was to become the IDF.

Adriano Directo Emperado: Adriano Directo Emperado (June 15, 1926 – April 4, 2009) was one of five martial artists who developed the kajukenbo self-defense system.

Amir Perets: Amir Perets (born 20 September 1974 in Tiberias, Israel) is an Israeli-born mixed martial artist, entrepreneur, and active participant in Fight Science featured on the National Geographic Channel.  He is an instrumental figure in popularizing the self-defense system of the Israeli Defense Forces known as Krav Maga.

Unit Egoz: Unit 621, otherwise known as Egoz (Hebrew: יחידת אגוז‎ ‎ , "Yehidat Egoz") is an elite Israel Defense Forces (IDF) special forces unit specializing in guerrilla warfare, special reconnaissance, and direct action (military).  Although a part of the IDF Central Command's 89th Brigade (commonly referred to as the commando brigade), its operators undergo basic training with the IDF Northern Command's Golani Brigade.

Sayokan: Sayokan is a contemporary Turkish martial art created by Nihat Yigit in 1999.  Sayokan has steered away from the memorization and rigidity of some traditional martial arts in favor of learning by concept.  Their idea is not to count on a series of memorized moves because the odds are high that something will go wrong.  Sayokan is a reality-based self-defense system developed from central Asian principals in combination with Ottoman style strikes and grappling moves.  Instead of memorizing many specific techniques, the Sayokan practitioner learns by strategy.

Imi Lichtenfeld: Emrich "Imi" Lichtenfeld (May 26, 1910 – January 9, 1998) was a Hungarian-born Israeli martial artist who founded the Krav Maga self-defense system.  He was also known as Imi Sde-Or, the Hebrew calque of his surname.

Ship Self-Defense System: The Ship Self-Defense System (SSDS) is a combat system specifically designed for anti-air defense of aircraft carriers, and most other non-Aegis United States Navy combat ships.  It coordinates several existing shipboard systems.  Multi-sensor integration, parallel processing and the coordination of hard and soft kill capabilities are key components of the SSDS.  Responses to airborne threats are based on automated or man-in-the-loop engagement doctrine.

Supporting paragraphs: Krav Maga Imi Lichtenfeld
Answer: Imi Sde-Or