Electronic commerce, commonly known as e-commerce or eCommerce, consists of the buying and selling of products or services over electronic systems such as the Internet and other computer networks. The amount of trade conducted electronically has grown extraordinarily with widespread Internet usage. The use of commerce is conducted in this way, spurring and drawing on innovations in electronic funds transfer, supply chain management, Internet marketing, online transaction processing, electronic data interchange (EDI), inventory management systems, and automated data collection systems. Modern electronic commerce typically uses the World Wide Web at least at some point in the transaction's lifecycle, although it can encompass a wider range of technologies such as e-mail, mobile devices and telephones as well.
Purchasing managers need to periodically evaluate supplier performance in order to retain those suppliers who meet their requirements in terms of several performance criteria. Six attributes frequently used as performance criteria are identified and used in this study. These attributes are: on-time delivery, quality, price/cost targets, professionalism, responsiveness to customer needs, and long-term relationships with the purchasing company. Purchasing managers use all six attributes jointly in evaluating supplier performance. Further, in making their choices the purchasing managers must necessarily make trade-offs among different levels of these attributes. Conjoint analysis is the appropriate method for measuring preferences where several attributes are used jointly in an overall evaluation. This article reports the results of an exploratory study examining the trade-offs made by Chinese purchasing managers among the six attributes identified earlier. The priorities of Chinese managers as well as the trade-offs they make are finally discussed in terms of their implications for Western marketers.
Data replication is an important technique for improving the performance, availability, ubiq-
uity, durability, and manageability of a broad range of large-scale applications such as personal
file systems, web services, enterprise data management systems, and grid computing. However,due to the fundamental trade-offs between consistency, availability, and performance , repli-cation systems must make compromises to suit the specific workloads or environments they aretargeting. My research focuses on finding the optimal tradeoffs for different real-world applica-tions by taking advantage of workload characteristics and/or application semantics and buildinga unified infrastructure to simplify the innovation and implementation of new tradeoffs for newenvironments.
Towards a Unified Theory of Replication
As technologies and workloads evolve, new replication systems will continue to be needed. Unfor-tunately, existing replication protocols and mechanisms are intrinsically entangled with specificpolicy assumptions. To accommodate new trade-offs for different policy requirements, new sys-tems are typically built from the ground up and co-mingle mechanisms and policies in their design.
The central thesis of my research is that there is a set of flexible common replication mechanisms that capture the right abstractions for replication and therefore can serve as a replication “micro-kernel” for building and deploying replication systems for different environments and workloads by simply defining the right policies on top of the mechanism layer.
PRACTI Replication. As a step towards realizing this vision, we first defined a taxonomy for
understanding replication systems based on three vital properties: (a) Partial Replication (PR)
means that any data can be replicated on any device; (b) Any Consistency (AC) means that the
system supports a range of consistency guarantees; and © Topology Independence (TI) means that information can flow between any pair of nodes.
2 Other Research
Although it is provably impossible to provide simultaneously optimal consistency, optimal avail-
ability, and optimal performance for general-case wide area network replication, we can, perhaps, provide nearly optimal behavior for specific applications by taking advantage of a given application’s semantics or/and workload characteristics. Here I briefly share my experience in applying this approach to solve edge-service problems.
Distributed E-commerce System. The emerging edge services architecture promises to im-
prove the availability and performance of web services by replicating servers at geographically
distributed sites. A key challenge in such systems is data replication and consistency, so that
edge server code can manipulate shared data without suffering the availability and performance
penalties that would be incurred by accessing a traditional centralized database. We use a dis-
tributed object architecture to build an edge service data replication system for an e-commerce
application, the TPC-W benchmark, which simulates an online bookstore . We take advantage
of application specific semantics to design distributed objects that each manages a specific subset of shared information using simple and effective consistency models. Our experimental results show that by slightly relaxing consistency within individual distributed objects, our application realizes both high availability and excellent performance. For example, in one experiment we find that our object-based edge server system provides five times better response time over a traditional centralized cluster architecture and a factor of nine improvement over an edge service system that distributes code but retains a centralized database.
Dual Quorum Replication. Dual-quorum replication  is a novel data replication algorithm
designed to support Internet edge services. Edge services allow clients to access Internet services
via distributed edge servers that operate on a shared collection of underlying data. We focus on
the key problem of sharing read/write data objects across a collection of edge servers when the
references to each object (a) tend not to exhibit high concurrency across multiple nodes and (b)
tend to exhibit bursts of read-dominated or write-dominated behavior.
3 Future Research
Offline Web Service Infrastructure. One interesting observation of the technology trends is
that in the last decade, the capacity of storage has grown by more than two orders of magnitude,whereas the bandwidth of network has not significantly improved. The un-matching growth of storage and network technologies favors widespread use of data replication for trading inexpensive storage to obtain improvements in human wait-time and productivity. With the fast growth of online applications and services and the need of accessing them from mobile devices, supporting online services “offline” is becoming a hot topic in the next generation of web applications.
The Hong Kong order of precedence is a nominal and symbolic hierarchy of important positions within the Government of Hong Kong. Administered by the government's Protocol Division, the hierarchy does not determine the order of succession for the office of Chief Executive, which is instead specified by the Basic Law of Hong Kong.
As a special administrative region of the People's Republic of China, Hong Kong maintains autonomy on all affairs other than defence and foreign relations. Reflecting that status, the order of precedence does not include state and party leaders of the Central People's Government. Government officials from mainland China are generally treated as special guests when attending Hong Kong government functions.
An order of precedence is a sequential hierarchy of nominal importance of items. Most often it is used in the context of people by many organizations and governments. It can also be used in context of decorations, medals and awards.
One's position in an order of precedence is not necessarily an indication of functional importance, but rather an indication of ceremonial or historical relevance; for instance, it may dictate where dignitaries are seated at formal dinners. Additionally, it may serve as the order of succession to determine who replaces the head of state in the event he or she is removed from office or incapacitated, although the two terms are not interchangeable in most cases.
What follow are general orders of precedence. They may be regarded as default rules upon which almost all more specific orders of precedence, for particular occasions or in particular institutions, are based. Universities and the professions often have their own rules of precedence applied locally based (for example) on university or professional rank, each rank then being ordered within itself on the basis of seniority (i.e. date of attaining that rank).
E-commerce (electronic commerce or EC) is the buying and selling of goods and services on the Internet, especially the World Wide Web. In practice, this term and a newer term, e-business, are often used interchangably. For online retail selling, the term e-tailing is sometimes used.
E-commerce can be divided into:
E-tailing or "virtual storefronts" on Web sites with online catalogs, sometimes gathered into a "virtual mall"
The gathering and use of demographic data through Web contacts
Electronic Data Interchange (EDI), the business-to-business exchange of data
E-mail and fax and their use as media for reaching prospects and established customers (for example, with newsletters)
Business-to-business buying and selling
The security of business transactions
E-tailing or The Virtual Storefront and the Virtual Mall
As a place for direct retail shopping, with its 24-hour availability, a global reach, the ability to interact and provide custom information and ordering, and multimedia prospects, the Web is rapidly becoming a multibillion dollar source of revenue for the world's businesses. A number of businesses already report considerable success. As early as the
• Retail industry
middle of 1997, Dell Computers reported orders of a million dollars a day. By early 1999, projected e-commerce revenues for business were in the billions of dollars and the stocks of companies deemed most adept at e-commerce were skyrocketing. Although many so-called dotcom retailers disappeared in the economic shakeout of 2000, Web retailing at sites such as Amazon.com, CDNow.com, and CompudataOnline.com continues to grow.
In early 1999, it was widely recognized that because of the interactive nature of the Internet, companies could gather data about prospects and customers in unprecedented amounts -through site registration, questionnaires, and as part of taking orders. The issue of whether data was being collected with the knowledge and permission of market subjects had been raised. (Microsoft referred to its policy of data collection as "profiling" and a proposed standard has been developed that allows Internet users to decide who can have what personal information.)
Electronic Data Interchange (EDI)
EDI is the exchange of business data using an understood data format. It predates today's Internet. EDI involves data exchange among parties that know each other well and make arrangements for one-to-one (or point-to-point) connection, usually dial-up. EDI is expected to be replaced by one or more standard XML formats, such as ebXML.
E-Mail, Fax, and Internet Telephony
E-commerce is also conducted through the more limited electronic forms of communication called e-mail, facsimile or fax, and the emerging use of telephone calls over the Internet. Most of this is business-to-business, with some companies attempting to use e-mail and fax for unsolicited ads (usually viewed as online junk mail or spam) to consumers and other business prospects. An increasing number of business Web sites offer e-mail newsletters for subscribers. A new trend is opt-in e-mail in which Web users voluntarily sign up to receive e-mail, usually sponsored or containing ads, about product categories or other subjects they are interested in.
Business-to-Business Buying and Selling
Thousands of companies that sell products to other companies have discovered that the Web provides not only a 24-hour-a-day showcase for their products but a quick way to reach the right people in a company for more information.
The Security of Business Transactions
Security includes authenticating business transactors, controlling access to resources such as Web pages for registered or selected users, encrypting communications, and, in general, ensuring the privacy and effectiveness of transactions. Among the most widely-used security technologies is the Secure Sockets Layer (SSL), which is built into both of the leading Web browsers
In summary, the early success of e-commerce enabled commercial transactions was more of a success than failure due to explosive growth in business and the credit economy. Many dot.com companies and investors had jump the gun in the 90’s, and were not prepared to take precaution till the Internet bubble burst. It was mostly associated with daunting costs and little paybacks in the form of intangibility. These e-commerce systems had various terms that include business-to-business, business-to-consumers, consumers-to-consumers and peer-to-peer. They are a part extension of e-commerce known as e-business systems. Finally, many nations and organisations still face limitations and barriers to e-commerce. A substantial investment of cost, know-how and technology awareness in e-commerce related issues such as cyber crime, and especially ethical and legal practices across international boundaries are essential