MSD 2011 Midterm Karl Lieberherr 3/28/20111MSD midterm

MSD 2011 Midterm

Karl Lieberherr

3/28/2011 1MSD midterm

1. Strengthening

1. add to oppose actions in scg.cd:1. OpposeRequest = Agree| Strengthen | Refute.

2. In scg.beh: AvatarI: strengthen public OpposeResponse strengthen(OpposeRequest request)?

3. Define how to use refutation protocol to deal with strengthening: Alice, proposes, Bob strengthens, Bob must defend strengthened claim against Alice.


2. Confidence• Add to claim definition in scg.cd• update valid function for Claim: confidence must

be in [0..1]. Make sure we have a valid function for Claim.

• Avatar propose needs to be updated: create claims with confidence. Random [0,1] for baby avatar.

• Influences playground level and SCG level.• Reputation update: make a proposal: multiply old

result with confidence.


Game Design

1. The cd2. valid3. quality4. Refutation protocol: ExistsForAll: “instance

from Alice” + “Solution of 0 from Bob”5. getResult: check if Bob’s solution has quality

1


Interfaces, Knowledge and Skillsof Playground Designer

1. SCG rules: how to play the game.2. Domain Knowledge, e.g., CSP.3. Define context-free grammars in EBNF style syntax4. Write programs in data-binding technology (common

in XML technology) (for baby avatar, etc.)5. The more domains, protocols, we have the more the

playground designer does configuration.6. Finding InstanceSets that lead to interesting games.

What are the niches for specialized, more efficient algorithms?

7. Request and Response object format for baby avatar.


PG Designers about scg.cd

• Claim fields must be in a certain order.• Styles of games• Protocol language


PG Designer about Protocols• List of available protocols• Should know basic predicate calculus (from logic) and

the connection between games and predicate logic. Prenex normal form?: all quantifiers at beginning.

• Difference between mathematical claims (for which a winning strategy corresponds to a proof) and other claims that must be settled using the game.

• Need for a new protocol? Provide a valid protocol definition

• Protocol negation: same domain: roles of Alice and Bob are reversed and a defense is changed into a refutation.


Not asked: Domain Designer

• Knows domain and standard solution approches. Knows about subdomains that have faster/customized solutions and offers those through instance sets.


Protocol Negation

!C=ExistsForAll !p• instance from Alice• solution sB of 0 from Bob• check: sB has quality <= t• Alice wins, Bob loses

C=ForAllExists p• instance from Bob• solution sA from Alice• check: sA has quality <=t• Alice loses, Bob wins


Protocol Negation 2

C = EA p(0,1)• Alice claims• Bob refutes• instance from Alice• solution of 0 from Bob• Alice defends iff p(0,1)

!C = AE !p(0,1)• Alice claims• Bob refutes• instance from Bob• solution of 0 from Alice• Alice is refuted iff p(0,1)

3/28/2011 MSD midterm 10

Alice <-> Bob, refute <-> defense

Modules

• SCG Court– defines SCG rules and what must be provided by

playground designer (structures, languages and interface implementations)

• Domain– defines languages and contracts of functions

• Protocol– scientific discourse and contract for outcome

• Playground: a configuration of a domain and claims in domain using protocol.


Hiding Complexity

• It is important to hide complexity from playground designers and avatar designers.

• A playground designer needs an abstract view of scg.cd and scg.beh. She needs only the signatures and contracts of methods, not their implementation, and she needs the languages defined in scg.cd.

• An avatar designer needs an abstract view of the implementation provided by the playground designer. Signatures and contracts. Playground designer must provide contracts for avatar designer.


Acceptance Test• Design 2 closely related new games

– MAX-SAT-ALL and MAX-SAT-SECRET• Domain: CNFs

– standard algorithm: generating a random assignment where each variable is set to true with probability p.

– InstanceSets: Length(k) = clauses are exactly of length k.

– quality(F,J) = fsat(F,J) = fraction of satisfied clauses.– valid(F,J) = all clauses in F evaluate to t or f– belongsTo(F,k) = all clauses use distinct literals and

are of length k


MAX-SAT-ALL(k)

• Protocol: ForAllExists(F,J) and its negation• Claims: MAX-SAT-ALL(k,t) = in CNFs in instance

set Length(k) there exists an assignment of at least quality t.


MAX-SAT-SECRET(k)

• Protocol: PositiveSecret(F,JA,JB) and its negation

• Claims: MAX-SAT-SECRET(k,t) = in CNFs in instance set Length(k) Alice’s JA approximates Bob’s secret solution JB within t.

• fsat(F,J)>=t


The Actions of an Avatar


propose C1

oppose/refute C2

oppose/strengthen C3

agree C4

I=provideInstance(C5)

S=solveInstance (I)

Scholar

Flow Game

• FlowClaim(c,G) = Exists flow F in G with value(F) >= c.

• Domain


Design Document forSCG Court Evolution

• It is important to prepare a design document for SCG Court that can be given to future developers of SCG Court to prepare them for SCG Court maintenance and evolution tasks.

• This document should outline the architecture of the system, using pictures. It should outline the “philosophy” used by the implementation teams so that this philosophy can also be followed during system maintenance.


• For example, the contract that the admin must check all incoming claim, instance and solution objects for validity (using valid(…) and belongsTo(…) must be mentioned.

• Please can the implementation teams write this document and present it at the last class.


• agile• development methodologies—and especially Extreme Programming—already incorporate the• three keys to test automation: (1) testers and programmers are expected to work together as a• single team, (2) the team treats test automation as a team responsibility and (3) testers are• expected to be engaged and testing throughout, often writing tests before code’s been written.• These tests, called acceptance tests, test the system from a customer perspective. The tests• themselves are variously written by product programmers, dedicated testers, or analysts acting in• the customer role. They use the testing framework created by the product programmers to• execute the tests. This is a significant difference from the traditional arrangement that assigns the• responsibility for test automation to an independent testing team.

• from: http://www.io.com/~wazmo/papers/design_for_testability_PNSQC.pdf


SCG

• train people to distinguish good claims from bad claims in a domain D where there is constructive evidence for defending good and refuting bad claims.

• good = true claim, optimal claim, recommended treatment for symptoms

• bad = false claim, non-optimal claim, non-recommended treatment for symptoms


Complexity

• distinguishing good claims from bad claims is hard.

• defending a good claim is easier• refuting a bad claim is easier


Claims

• and, or, not, ForAll, Exists• basic claims are decided by refutation

protocol


Behaviors• good

– propose good claim and defend it.– agree with good claim and defend it and refute negation.– oppose bad claim and refute or strengthen it.

• bad– propose bad claim.– fail to

• refute bad claim• defend good claim


Documents

MSD 2011 Midterm Karl Lieberherr 3/28/20111MSD midterm