Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: utzoo!watmath!clyde!burl!ulysses!cbosgd!ucbvax!ailist From: AIList-REQUEST@SRI-AI.ARPA (AIList Moderator Kenneth Laws) Newsgroups: mod.ai Subject: AIList Digest V4 #2 Message-ID: <8601081812.AA14645@ucbvax.berkeley.edu> Date: Wed, 8-Jan-86 11:57:00 EST Article-I.D.: ucbvax.8601081812.AA14645 Posted: Wed Jan 8 11:57:00 1986 Date-Received: Thu, 9-Jan-86 03:30:50 EST Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: AIList@SRI-AI Organization: The ARPA Internet Lines: 322 Approved: ailist@sri-ai.arpa AIList Digest Wednesday, 8 Jan 1986 Volume 4 : Issue 2 Today's Topics: Corrections - Feigenbaum's Comments & Xerox Reader Count, Query - AI Paradigm, Review - Stanford SDI Debate (12/19) ---------------------------------------------------------------------- Date: Sun 29 Dec 85 22:18:33-PST From: Edward Feigenbaum Subject: re the news report on my speech in the Netherlands Saw my name in the Fri 27 Dec. 1985 AIList Digest V3 #192. Since it's best not to let silly things propagate, let me say here what I said (I actually said many many things; I don't understand why those few things were picked out). I said that among the most commercially important applications of expert systems in the next ten years would be factory management applications and financial service applications. (I didn't even mention factory automation). I said that speech understanding applications would become economically very important. (I never mentioned speech generation.) Best wishes for a journalistically accurate New Year (fat chance), Ed Feigenbaum ------------------------------ Date: 6 Jan 86 16:22 PST From: Newman.pasa@Xerox.ARPA Subject: Reader Count I don't know if you want to post this to the net or not, but in the interest of accuracy, Xerox has approximately 248 readers of the AIList. >>Dave ------------------------------ Date: Tuesday, 7 January 1986 02:19:31 EST From: Duvvuru.Sriram@cive.ri.cmu.edu Subject: AI Paradigm I have seen the word "AI Paradigm" in several papers/reports. My dictionary [Random House] says that a Paradigm is either an example or a model. Is there any other meaning to it or is it just a better word for "example"? Sriram ------------------------------ Date: Tue, 31 Dec 85 11:55:37 pst From: jrisberg@aids-unix (Jeff Risberg) Subject: Stanford SDI debate (12/19) summary The following is a somewhat long summary of the technical debate on SDI entitled "SDI: How Feasible, How Useful, How Robust?" that was held at Stanford on December 19th. Since this debate was announced on AILIST, we felt that readers would be interested in this summary. [I was reluctant to permit the initial announcement and I am reluctant to permit the summary. I have decided to forward them because SDI may well involve major funding in the area of AI. Please restrict any discussion in AIList to the areas of AI, pattern recognition, or the feasibility of distributed decision making. Political discussions would be more appropriate on Arms-D@MIT-MC, Risks@SRI-NIC, or perhaps Space@MIT-MC. -- KIL] The panelists at the debate were: Advocates: Professor Richard Lipton, Professor of Computer Science at Princeton University, current member of SDIO's Panel on Computing and Support of Battle Management. Major Simon Peter Worden, the Special Assistant to the Director of the SDIO and Technical Advisor to the Nuclear and Space Arms Talk with the USSR in Geneva. Opponents: Dr. Richard L. Garwin, IBM Fellow and Adjunct Professor of Physics at Columbia University, Physicist and Defense Consultant. Professor David Parnas, Lansdown Professor of Computer Science at the University of Victoria, former member of the SDI Organization's Panel on Computing and Support of Battle Management. Dr. Goldberger, President of CalTech, served as the moderator of the discussion. He presented a bit of history relating to the subject of defensive warfare and then allowed the panelists to speak. There are certainly historical precedents for defensive systems, in fact, each US leader since the 1950's has sought a defense. SDI is simply the largest scale and most visible concept to date. Because of the complexity of the issue, a question like "can it work?" can only be answered by determining 'what does "can" mean?', 'what does "it" mean?', and 'what does "work" mean?'. There have been various justifications proposed for SDI, and the technical and political community has raised numerous questions. The format of the debate consisted of three sections: during the first section, each speaker was allowed 20 minutes with which to present his case; following that, each speaker had a 5-minute rebuttal period; finally, the audience was allowed to ask questions via screened 3 x 5 index cards. Major Worden spoke first and discussed some positive aspects of SDI. In his view, the principal justification is for Arms Control. In that view, a major goal is that the SDI system have a lower marginal cost than that of building additional offensive systems. Survivability is another goal. He said that the object of SDIO is to establish the feasibility of the system, but not to build it. Similarly, it may not involve space weapons, although most of the current concepts include a space segment. We would also like to get the Soviets to admit their own work in such systems. They regularly deny such work, but when we show them ariel photos of their high-power lasers, they say, "Oh, we do have laser research for medical purposes". The numerical aspects of a Defensive Reliant Deterance are that each layer of defense drives the number of offensive warheads needed up further. There are a series of layers, with each layer consisting of sensors, weapons, and battle management systems. He showed some of the standard slides of this design. The concept is "Proliferated and Distributed". They are planning for the late 1990's. The key issue as he sees it is countermeasures, such as the fast burn booster. There are three types of threats and five types of countermeasures. He expected that countermeasures will develop much as aircraft gained shielding, speed, and proliferation countermeasures after WW I. He gave a cost context of the project in comparison to the cost of insurance in the private sector. The cost of insurance is over $300 billion/year, while the SDI work is currently costing $1.5 billion. Major Worden admitted that President Reagan caught everyone off guard with his speech about SDI two years ago. Dr. Garwin spoke next. He recommended that we think carefully about just what are the goals, costs, and likely Soviet Response to SDI. He said that the Scowcroft Commission reported that U.S. security could be maintained without SDI. His opinion is that while SDI has been proposed to replace deterrance, it is really simply another form of deterrance. He is concerned with the layered approach of the system in that there is catastrophic failure if one layer does not do its job. For example, the design of each layer assumes that the prior one does its job in reducing the number of incoming objects. Examples of potential areas of failure were given: space mines could easily knock out any space segment units and midcourse intercept could be overwhelmed by large numbers of decoys. Dr. Garwin feels that the systems needed for SDI can not be built under the ABM treaty. There has been a progression of goals, and in effect "replace deterance" has become "strengthen deterance". He closed by describing his view of a viable strategic balance, which would be to limit each side to 1000 warheads, deployed on small missiles, small subs, and cruise missiles, with no counterforce threats against strategic targets. Preserve the ADM treaty. BMD research may be continued, in order to confirm that there is no threat to the system. Dr. Lipton was the next speaker. He joined the technical panel of SDIO last summer. (An interesting point is that Dr. Lipton is a former student of Dr. Parnas.) His major focus was in the importance of the de-centralization of software. The Fletcher panel design was centralized, with software in charge of everything. "Is it possible to build a system without these problems?" Discussion of feasibility must encompass all design possibilities, and Lipton stressed the merits of a decentralized design. He led into this by an analogy with the banking industry. Banking works because it is a large collection of loosely organized components. In the SDI example, he refered to large numbers of satellite groups handling independent battle management functions. Fault tolerance would provide reliability, like the concept of the strategic weapons triad. He argued that these seperate groups would be testable, by putting a few into orbit and shooting missiles at them. The false alarm problem could be controlled by activating different numbers of systems. Coordination problems were raised by the Fletcher panel toward a goal of conserving "bullets". Dr. Lipton's studies indicated that the shot overhead of low coordination is not that high. Dr. Parnas spoke last. He had good points in his speech, but had a problem with becoming quite caustic in his remarks about the SDIO members. He said that (loosely quoted) "I used to feel that arms control people are guilty of wishful thinking, but I have now seen a whole new standard." His major complaint against SDI is that SDI forces us to trust the system; if SDI need not be perfect, it must at least be trustworthy, and he feels that this is not possible. Conditions for validation include: mathematical analysis, exhaustive case analysis, or prolonged, realistic testing. Even after one or more of these conditions have been met, the system must still be operated under controlled conditions. The validation of software is inherently different from the standard engineering problems such as bridge design. Something different about software. It is made up of discrete, rather than continuous functions. Thus design principles such as building for twice the weight do not truly apply, but instead, the number of discrete cases must be examined, along with thorough testing. Even after a number of years of use, bugs may still be found. True testing requires thousands of years. For most software, we can allow unreliable software, as long as we trust it. For SDI, we cannot. He doesn't believe that de-centralization provides added trustworthiness to the system. He stated that he never took the Fletcher design seriously in the first place, feeling it that was no more than a rough sizing of the problem. There are a series of myths around de-centralization. Dr. Parnas' final point is that SDI is not a limit of computers, but of human beings. The rebuttals were then held. Major Worden questioned the meaning of deterence and then mentioned some possible alternatives to SDI: automatic launch under attack, preventive attacks, and bombs under U.S. cities. He indicated that Dr. Garwin had shown only that he could design a system that SDIO wouldn't buy. His final comment re-iterated the linkage of SDI to the arms control process. Dr. Garwin (and the others) kept mentioning the Scowcroft report which produced possible defensive measures other than SDI. Dr. Garwin pointed out that Dr. Lipton had only found that the system proposed by Fletcher might not work, but that Lipton believed others might. In any case, so long as Soviets can deliver by other means (cruise missiles), we will continue to need deterance. Dr. Lipton restated his belief in the need for independent systems. He recognized that nothing is perfect, that even computers are not reliable, but they are used on a daily basis. The use of independent battle stations would stress the sensors, but he argued that teraflops would alleviate the need for independent views. Dr. Parnas again made a couple of inappropriate shots..."I've been to a lot of Mickey Mouse meetings, but the ones sponsored by SDI had the biggest ears and biggest nose I've ever seen." He thinks that the idea of separate systems does not remove the size or complexity of what is needed; dividing 10 million lines of code into small modules of 1000 lines does still not ensure error-free code. People do not write independent code. Questions raised from the floor asked about different types of lasers, the time to phase-in to SDI, and about the non-ICBM threat. Worden replied that cruise missiles are not strategic weapons because of their flight time, and that smuggling bombs into the US would not be a realistic approach for a Soviet leader to taken. The speakers then made closing comments: Dr. Garwin said that we currently have a real opportunity for arms reduction. This would be much more survivable than continued escalation and research into defensive weaponry. He feels that both sides should abandon defense efforts. Control of nuclear proliferation is essential. Major Worden agreed with these points of Dr. Garwin, but said that it is necessary and vital to carry forward a defensive program within the ABM treaty to provide a different kind of security. Dr. Parnas said that in software, the engineering term of "tolerance" depends on continuity. "Almost right" does not make sense in the context of SDI. He fears espionage that would result in someone getting a copy of the software. Reasons for not going ahead with SDI anyway include the lost opportunity for other projects, low quality of results, and weakening of the strategic position. Dr. Lipton said that if the independent segments of the SDI system do not interact, the code is not vulnerable. He pointed out that there are simple systems, such as elevators, that we do trust. Dr. Goldberger then made some closing comments. He said that strategic defense and arms control must be approached seriously. The laws of physics are immune to political views and we are currently at a critical political point. A decision to push forward defensively without a reduction in offense would be a mistake. SDI has been proposed as part of current moves toward lowering threat of destruction, yet it is difficult, with verification problems, and major risks. He hopes that the human spirit will prevail in the decisions that must be made. In summary, the debate was quite interesting, although inconclusive if judged in a strict manner. We were most surprised that software technical details were hardly mentioned, and that political and non computer technology issues were the focus of the discussion. Dr. Parnas and Dr. Lipton made several comments against each other, which detracted from the technical discussion. It didn't appear that Dr. Lipton was overly familiar with the SDI problems; he continually talked in generalities, with few facts with which to back up his statements. Dr. Garwin and Major Worden were much more prepared in their talks and didn't take any cheap shots with which to score points with the audience. The comments above are strictly our personal opinions and not representative of any organization. Jeff Risberg (jrisberg@aids-unix) Susan Rosenbaum (susan@aids-unix) ------------------------------ End of AIList Digest ********************