An application reaches a steady-state whenever it has no outstanding requests; i.e., it has no pending requests and all of the responses to its current set of requests have been completely received or received to the point where they can be treated as a representation data stream. For a browser application, this state corresponds to a "web page," including the primary representation and ancillary representations, such as in-line images, embedded applets, and style sheets. The significance of application steady-states is seen in their impact on both user-perceived performance and the burstiness of network request traffic.
All REST interactions are stateless. That is, each request contains all of the information necessary for a connector to understand the request, independent of any requests that may have preceded it. This restriction accomplishes four functions: 1) it removes any need for the connectors to retain application state between requests, thus reducing consumption of physical resources and improving scalability; 2) it allows interactions to be processed in parallel without requiring that the processing mechanism understand the interaction semantics; 3) it allows an intermediary to view and understand a request in isolation, which may be necessary when services are dynamically rearranged; and, 4) it forces all of the information that might factor into the reusability of a cached response to be present in each request.
This abstract definition of a resource enables key features of the Web architecture. First, it provides generality by encompassing many sources of information without artificially distinguishing them by type or implementation. Second, it allows late binding of the reference to a representation, enabling content negotiation to take place based on characteristics of the request. Finally, it allows an author to reference the concept rather than some singular representation of that concept, thus removing the need to change all existing links whenever the representation changes (assuming the author used the right identifier).
This chapter introduces and elaborates the Representational State Transfer (REST) architectural style for distributed hypermedia systems, describing the software engineering principles guiding REST and the interaction constraints chosen to retain those principles, while contrasting them to the constraints of other architectural styles. REST is a hybrid style derived from several of the network-based architectural styles described in Chapter 3 and combined with additional constraints that define a uniform connector interface. The software architecture framework of Chapter 1 is used to define the architectural elements of REST and examine sample process, connector, and data views of prototypical architectures.
The application state is controlled and stored by the user agent and can be composed of representations from multiple servers. In addition to freeing the server from the scalability problems of storing state, this allows the user to directly manipulate the state (e.g., a Web browser's history), anticipate changes to that state (e.g., link maps and prefetching of representations), and jump from one application to another (e.g., bookmarks and URI-entry dialogs).
Following on from the previous implementation of laws designed to encourage recycling and other waste limiting practices; the upcoming legislation is indicative of growing momentum in Indonesia to tackle its present shortcomings in waste management infrastructure and facilities. Amid this stricter regulatory climate and increasing demand for comprehensive waste disposal services, foreign investors are presented with new opportunities in Indonesia to enter the waste management and recycling sector.
Following this structured presentation the committee begins to ask questions,but as can be expected the questions follow along with the wall chartsand the whole discussion proceeds in an orderly manner. If guests are presentat the defense, this form of presentation helps them also follow alongand understand exactly what was accomplished through the research.
Less constrained by land limitations than Singapore, Indonesia also presents opportunities in a composting industry now more attractive due to an increasing awareness amongst the general public of the need to separate organic from inorganic waste. Initiatives from local governments and private sector players such as Unilever Indonesia to introduce the concept of waste banks -- in which households separate their waste into different containers and then deposit non-organic solid waste at a collection point in their neighborhood in exchange for money that can be kept in an account at the waste bank or withdrawn – have had a substantial impact across the country in educating consumers and changing their behavior. Over 14,000 kg of inorganic waste was collected by local communities in Greater Jakarta less than a year after Unilever Indonesia’s program set up 10 waste banks in the area. This movement also leads to the creation of centralized recycling and collection points that build towards the basic infrastructure needed for lucrative composting business opportunities in Indonesia.
I ask the student to prepare a 20-25 minute presentation that reviewsthe entire study. This is done through the help of a series of 10-12 largepieces of paper, wall charts, that have been posted sequentially aroundthe walls of the room. Each piece of paper contains key words regardingeach of the different aspects of the study. Some pieces of paper containinformation about the study setting, questions and methodology. Other piecesof paper present findings and finally there are those pieces that presentthe conclusions and implications. By preparing these wall charts aheadof time the student is able to relax during the presentation and use thepieces of paper as if they were a road map toward the goal. No matter hownervous you are you can always let the wall charts guide YOU throughyour presentation. Lettering is done with a dark marking pen and extranotes are included in very small printing with a pencil (that no one canreally see). We've also tried it with overhead projected transparenciesbut it doesn't work as well. With the transparencies they're gone fromview after a few seconds. The wall charts stay up for everyone to see andto help focus attention.
Driving the emergence of Indonesia’s waste management and recycling sector are several trends that beget its positive long term outlook. The present boom in consumption necessitates a rise in the use of plastics and packaging that require advanced waste management techniques to avoid adding to Indonesia’s already dangerously full landfills. The country’s high birth rate brings about opportunities in a niche composting industry that has proven successful in markets abroad. Finally, growing demand for energy and the government’s long term plan to move away from fossil fuels places a spotlight on renewable energy and opens the door to the establishment of waste fuelled power plants used to great effect in other ASEAN countries. With these trends providing the momentum that propels the sector forward, Indonesia’s waste management and recycling businesses should expect to reap the rewards of future market growth set to widen the scope of opportunities in this presently underserved field.
29. Now it's time to write the last chapter. But what chapter is thelast one? My perception is that the last chapter should be the first chapter.I don't really mean this in the literal sense. Certainly youwrote Chapter One at the beginning of this whole process. Now, at the end,it's time to "rewrite" Chapter One. After you've had a chanceto write your dissertation all the way to the end, the last thing you shoulddo is turn back to Chapter One. Reread Chapter One carefully with the insightyou now have from having completed Chapter Five. Does Chapter One clearlyhelp the reader move in the direction of Chapter Five? Are important conceptsthat will be necessary for understanding Chapter Five presented in ChapterOne?