Time: 2.8 hours
Surya Nepal, Zaki Malik, Athman Bouguettaya, "Reputation Propagation in Composite Services," icws, pp.295-302, 2009 IEEE International Conference on Web Services, 2009
作者Surya Nepal目前是CSIRO ICT centre的Principal Research Scientist, 方向是trust aspects of Service Computing. 本文要解决的问题是如何将用户针对composite web service的reputation值分配给组成服务("developing a method of distribution of reputation received by a composite service to its component services").
1. 概念
trust: the belief that a service consumer has about the intention and ability of a service provider to act as expected.
reputation: a mechanism of establishing the belief about the provider's ability to deliver, through collective perception of the consumers that have interacted with the service provider in the past.
2. Service Composition Scenario (S2)
Vertical composition
有点类似"centralized service composition", 有两个特点: (1) component service向composite service报告, component services之间不直接交互 (2)"sub-contracting" task of the service to other parites.
这个第二点似乎就是指"成员服务本身也是一个composite service"的情况.
Horizontal composition
model a "supply-chain" like combination of services, 类似"decentralized service composition".
Hybrid composition
本文讨论的是vertaical composition的情形.
3. (S3)本文提出了一种"contribution-based distribution of reputation method"来讲reputation分配给component services, 分为3步:
Contribution Vector Production –> Distribution Vector Derivation –> Reputation Propagation
这一章节的一些疑问
(1) 文中公式(3)缺少符号的解释. 这个公式是用来计算组成服务的reputation的, 有几个疑问: 为什么是求积? 为什么是t-1到t-k?为什么(s, C)t? where后面的那个东西是哪里冒出来的? 
(2) contributor vector计算出来以后, 之后就没有用到过?
(3) 对整套计算方法的有效性也有怀疑.
有机会会再看一下这篇.