Showing posts with label world wide web. Show all posts
Showing posts with label world wide web. Show all posts

Monday, 25 February 2008

debatepedia.com

A more informative, objective and academic approach to online debate and argumentation, imposing greater structure and rules on contributors and contributions. Check it out here.

Sunday, 9 September 2007

31, Customer Coalitions in Electronic Markets

Notes taken from 'Customer Coalitions in Electronic Markets' (2001), by Maksim Tsvetovat, Katia Sycara, Yian Chen, and James Ying

"... In this paper, we report on coalition formation as a means to formation of groups of customers coming together to procure goods at a volume discount ("buying clubs") and economic incentives for creation of such group..."

1, Introduction

A coalition is a set of self-interested agents that agree to cooperate to execute a task or achieve a goal.

2, Prior Work

3, Incentives for Customer Coalitions

(Supplier Incentive to Sell Wholesale; Customer Incentive to Buy Wholesale)

4, Coalitions and Wholesale Purchasing

In the real world, a single customer rarely wants to buy large enough quantities of goods to justify wholesale purchasing... In order to lower the purchase price (and, therefore, increase utility), self-interested customer agents can join in a coalition... This would enable the coalition to buy a wholesale lot from the supplier, break it into sub-lots and distribute them to its members, thus raising the utility of each individual member.

However, the formation and administration of coalitions, as well as distribution of sub-lots has its costs... In particular, such costs include the cost of administering coalition membership, cost of collecting payments from individual memberships, and the cost of distributing items to the members when the transaction is complete. In some cases (such as distributing copies of software) some of the costs can be very small, and in other cases may rise to be prohibitively large.

5, Coalition Models

It is possible to construct a number of coalition models and protocols, all of which would have different properties and requirements. In general, all coalition models include several stages:
- Negotiation
- Coalition Formation
- Leader Election/Voting
- Payment Collection
- Execution/Distribution stage

In design of coalition protocols, the following issues have to be taken into account:
- Coalition Stability
- Distribution of Gain
- Distribution of Costs and Utility
- Distribution of Risk
- Trust and Certification

Most coalition protocols can be divided into two classes (pre-negotiation and post-negotiation), based on the order in which negotiation and coalition forming happen...

(Post-negotiation; Pre-negotiation; Distribution of Costs and Utility)

6, Customer Coalitions for Volume Discounts - An Implementation

(Coalition Protocol; Testbed Architecture; Implementation of Agents; PiPL Language)

7, Conclusions and Future Work

30, Bid Together, Buy Together

Notes taken from 'Bid Together, Buy Together: On the Efficacy of Group-Buying Business Models in Internet-based Selling' (2001), by Robert J. Kauffman and Bin Wang

"... Dynamic pricing approaches are used by many well known Internet-based firms, including firms that offer online auctions such as eBay and Amazon.com. A group-buying discount is a dynamic pricing mechanism that mimics the general approach of traditional "discount shopping clubs". Group buying pricing mechanisms permit buyers to aggregate their purchasing power and obtain lower prices than they otherwise would be able to get individually..."

1, Introduction

Model type: Group-buying models
Key concept: Enable buyers to obtain lower prices, as more people indicate a willingness to buy from the Internet-based seller's Web site. There are two variaties, involving group-buying with a fixed time period to completion of an auction, and group-buying with a fixed price that is achieved only when enough buyers participate.

... In a discussion on the recent closure of Mercata, Cook (2001) points out that the group-buying business model is too difficult for the general concumer to understand. The author also argues that the mechanics of group-buying on the Internet also prevent impulse buying, due to the lengthy periods consumers have to wait until until the end of the auction cycles that characterize group-buying market mechanisms. More importantly, he argues that the transaction volume on group-buying sites is much smaller than those of the traditional discount stores, which makes it difficult for group-buying sites to compete with retial giants such as Wal-Mart and Target...

2, The Basics of Group-Buying Models in E-Commerce

2.1, The Market Mechanisms

Pricing to match buyers and sellers is an important function of a market. In the bricks-and-mortar world, posted pricing mechanisms have been the dominant pricing strategies, where retailers display the prices they ask for the merchandise and consumers decide whether they would accept the prices or not. Under dynamic pricing mechanisms, however, buyers are no longer left with this take-it-or-leave-it decision. They can actively negotiate with the sellers to reach a satisfactory price...

2.2, The Value Proposition for Group-Buying on the Internet

The primary value proposition of group-buying business models to consumers is the lower prices they can provide, due to the buyers' collective bargaining power. By accumulating a large number of orders in a short period of time, group-buying Web sites claim they can negotiate low prices with manufacturers and suppliers, and then pass these savings on to their customers...

3, Buyer Behaviour and Market Competition in Group-Buying

(Buyer Behaviour Under the Group-Buying Market Microstructure; The Anticipation of a Price Drop; The Group-Buying Mentality; The Price Threshold Effect; Competition in the Group-Buying Market)

... The "Save-a-Spot" feature at Mobshop allowed shoppers to place conditional bids at lower prices if they were dissatisfied with the current price. The created a win-win situation for both the firm and its customers... Thus, customers did not incur the risk of buying at prices higher than they were willing to pay... And so we see that, under the group-buying market microstructure, consumers have the oppurtunity to collaborate with each other to get lower prices, instead of simply bidding against each other in auctions. Hence, consumers have the incentive to recruit other shoppers...

4, A Framework for Comparing Group-Buying Websites

Based on our survey of the group-buying websites, we identified two primary kinds of customer targeting strategies: business-to-customer (B2C) and business-to-business (B2B). The B2B category also includes the education and government procurement. We also distinguish whether a buyer or a seller initiates the auction cycle... Finally, we note that the demand aggregation approach can be determined by whether the Web site is a destination site or a site with a distributed-service model (e.g. embedded in other Web sites)...

(Mercata.com; Mobshop.com; LetsBuyIt.com; Other Group-Buying Websites)

5, Analyzing Group-Buying Business Models

Some Dimensions for Comparing Group-Buying Business Models:
- Industry Studies
- How Do Prices on Group-Buying Web Sites Compare With Other Firms' Prices?

Comparing Rivals: Mercata and Mobshop
- Pricing Strategy
- Information Endowment
- Site Features
- Product Emphasis
- Pre-Trade and Post-Trade Logistics

Discussion
(1) In which market does the group-buying model work best, B2C or B2B?
(2) How should firms that are focusing on the B2C market compete with other business models for limited customer resources?
(3) What do we learn about the composition of effective product offerings at group-buying Web sites?
(4) To what extent are group-buying Web sites at a disadvantage when it comes to the use of shopbots for comparison shopping?

6, Conclusion

Sunday, 15 April 2007

18, A Semantic Web Primer

Summary of ‘A Semantic Web Primer’ by Grigoris Antoniou and Frank van Harmelen (2004)

1, The Semantic Web Vision

- The Semantic is an initiative that aims at improving the current state of the World Wide Web.
- The key idea is the use of machine-processable Web information.
- Key technologies include explicit metadata, ontologies, logic and inferencing, and intelligent agents.
- The development of the Semantic Web proceeds in layers.

2, Structured Web Documents in XML

- XML is a metalanguage that allows users to define markup for their documents using tags.
- Nesting of tags introduces structure. The structure of documents can be enforced schemas or DTDs.
- XML separates content and structure from formatting.
- XML is the de facto standard for the representation of structured information on the Web and supports machine processing of information.
- XML supports the exchange of structured information across different applications through markup, structure, and transformations.
- XML is supported by query languages.

Some points discussed in subsequent chapters include:
- The nesting of tags does not have standard meaning.
- The semantics of XML documents is not accessible to machines, only to people.
- Collaboration and exchange are supported if there is an underlying shared understanding of the vocabulary. XML is well-suited for close collaboration, where domain- or community-based vocabularies are used. It is not so well suited for global communication.

3, Describing Web Resources in RDF

- RDF provides a foundation for representing and processing metadata.
- RDF has a graph-based data model. Its key concepts are resource, property, and statement. A statement is a resource-property-value triple.
- RDF has an XML-based syntax to support syntactic interoperability. XML and RDF complement each other because RDF supports semantic interoperability.
- RDF has a decentralised philosophy and allows incremental building of knowledge, and its sharing and reuse.
- RDF is domain-independent. RDF Schema provides a mechanism for describing specific domains.
- RDF Schema is a primitive ontology language. It offers certain modelling primitives with fixed meaning. Key concepts of RDF Schema are class, subclass relations, property, subproperty relations, and domain and range restrictions.
- There exist query languages for RDF and RDFS.

Some points that will be discussed in the next chapter:
- RDF Schema is quite primitive as a modelling language for the Web. Many desirable modelling primitives are missing.
- Therefore we need an ontology layer on top of RDF/RDFS.

4, Web Ontology Language: OWL

- OWL is the proposed standard for Web ontologies. It allows us to describe the semantics of knowledge in a machine-accessible way.
- OWL builds upon RDF and RDF Schema: (XML-based) RDF syntax is used; instances are defined using RDF descriptions; and most RDFS modelling primitives are used.
- Formal semantics and reasoning support is provided through the mapping of OWL on logics. Predicate logic and description logics have been used for this purpose.

While OWL is sufficiently rich to be used in practice, extensions are in the making. They will provide further logical features, including rules.

5, Logic and Inference: Rules

- Horn logic is a subset of predicate logic that allows efficient reasoning. It forms a subset orthogonal to description logics.
- Horn logic is the basis of monotonic rules.
- Non-monotonic rules are useful in situations where the available information is incomplete. They are rules that may be overridden by contrary evidence (other rules).
- Priorities are used to resolve some conflicts between non-monotonic rules.
- The representation of rules in XML-like languages is straightforward.

Monday, 26 March 2007

14, The Search

Quotes taken from ‘The Search: How Google and its rivals rewrote the rules of business and transformed our culture’ (2005) by John Battelle

Page 1 - The Database of Intentions
“The library of Alexandria was the first time humanity attempted to bring the sum total of human knowledge together in one place at one time. Our latest attempt? Google.” (Brewster Kahle, entrepreneur and founder, the Internet Archive)

Page 19 – Who, What, Where, Why, When, and How (Much)
“Judge of a man by his questions, rather than by his answers.” (Voltaire)

Page 262 – The Perfect Search (Search as the New Interface)
… A9 has broken search into its two most basic parts. Recovery is everywhere you’ve been before (and might want to go again); discovery is everything you may wish to find, but have yet to encounter. A9 attacks recovery through its search history feature and toolbar, which tracks every site you visit. The discovery feature finds sites you might be interested in on the basis of your clickstream and – here’s the neat part – the clickstream of others…

Page 263-266 – The Perfect Search (The Semantic Web?)
But perfect search will require more than ubiquity, clickstreams, and personalisation. The vast corpus of information now available to us is often meaningless unless it is somehow tagged – identified in such a way that search engines can best make sense of it and serve it up to us. Many in the search industry believe search will be revolutionised by what is called metadata. Clickstreams are a form of metadata – information about where you go and what you choose as you browse the Web. But to get to more perfect search, we need to create a more intelligent Web. That means tagging the relatively dumb Web pages that make up most of the Web as we know it today with some kind of code that declares, in a machine-readable universal lingo, what they are, what they are capable of doing, and how they might change over time.

This is the vision of the semantic Web… While it’s always dangerous to lean too heavily on metaphor, the basic idea is that with semantic tags, the Web becomes more like a structured database… making it far easier to find things. This in turn allows the rules of logic, or reason, into the equation.

This structure also makes it easier to do things, to execute complex tasks built upon finding things – scheduling a meeting, planning a trip, organising a wedding, you name it…

But a major hurdle to the rise of the semantic Web has been standards: who gets to say which tags are right for which pages? If there is a picture of a Cape Cod seashore on the Web, should it be tagged as “beach”, “shore”, “ocean”, or any number of other possible words? As Yahoo learned early in its directory days, the nearly limitless possibilities of the Web do not lend themselves to top-down, human-driven solutions.

Again, this is where the Force of the Many comes in. In late 2004 and throughout 2005, a new kind of tagging scheme arose, one based not on any strict, top-down hierarchy, but rather on a messy, bottom-up approach. Small start-up companies like Flickr, Technorati (a weblog search engine), and del.icio.us (a link sharing site) began giving their users the ability to tag anything they saw, and then to share those tags with others. By letting anyone tag anything, the theory goes, ultimately a kind of fuzzy relevance for any given item will emerge. The photo of the Cape Cod seascape, for example, will probably be tagged with all the possible descriptors. That way, no matter what phrase a person uses to search it, whether it’s “ocean photos” or “Cape Cod seascapes,” the photo will be found.

Early bloggers dubbed this approach folksonomies – folk + taxonomy – and the movement is gaining momentum…

Page 280 – Perfect Search (The search for perfection)
Whatever your first search moment was, there will be many, many more as the space evolves. Search is no longer a standalone application, a useful but impersonal tool for finding something on a new medium called the World Wide Web. Increasingly, search is our mechanism for how we understand ourselves, our world, and our place within it. It’s how we navigate the one infinite resource that drives human culture: knowledge. Perfect search – every single possible bit of information at our fingertips, perfectly contexualised, perfectly personalised – may never be realised. But the journey to find out if it is just might be is certainly going to be fun.