Rafflesia Species in Malaysia Identification
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Published: Mon, 26 Feb 2018
1.1 BACKGROUND STUDY
There are a number of unique plant types in the world which are on the brink of extinction, or are so extremely limited in range. For example the beautiful palms such as the Talipot Palm (Corypha elata), Johannis teysmannia in Sarawak and Malaya, and also Livistona in West Sumatra. The largest flower in the world, Rafflesia arnoldii and related species, are going to vanish unless more nature reserves are created for such remarkable plants in Sumatra, Borneo, Java, and the Philippines.
Rafflesia is a genus of flowering plants that is made up of 23 known species. The best known of these species is Rafflesia arboldii which has the distinction of being the world’s largest flower, reaching a diameter of about three feet. The genus Rafflesia gets its name from Sir Stamford Raffles, the founder of the British colony of Singapore (Walter et al., 1998).
Rafflesia is a unique plant because of its dimensions unlike other flowers. This circumstance makes it widely known. It is also become an icon for conservation especially of the rain forest area. The rarity creates interest among nature lovers, tourists and the general public. The fact that some species may be in the brink of extinction alarms conservation groups. Its little-known biology and reproductive ecology spurs the interest of botanists and ecologist (Nais, 2004). Rafflesia is also thought to be one of the rarest of all plant genera which is only found in Borneo, Sumatra, Java, Peninsular Malaysia, Thailand and the Philippines.
1.2 PROBLEM STATEMENT
Malaysia is very fortunate for being one of the habitats of Rafflesia. But unfortunately, all of the known species of Rafflesia are threatened or endangered. In Malaysia the Rafflesia is only a “Totally Protected Plant” by law in Sarawak. In Sabah and Peninsular Malaysia it is only safeguarded by laws when found in protected areas like National or State Parks. In 2002, 44 out of the 83 Rafflesia flowers found in Sabah were outside of designated conservation places (Sabah Travel Guide, 2004).
Eight out of the 23 known species of Rafflesia can be found in Malaysia, most of them in the jungles on the island of Borneo. Some species of Rafflesia are endemic species. That means these species are native and can be found only in that location. For example, Rafflesia tengku-adlinii seems to be endemic to Sabah only while Rafflesia tuan-mudae endemic to Sarawak only. Because the Rafflesia is only found in specific areas and its locations often difficult to reach, and because it only blooms for a very short time, its life cycle or the methods of pollination and seed dispersal is very unclear. This makes the appropriate methods to conserve it quite difficult to be found.
Other than that, in Peninsular Malaysia flower buds are still sold as traditional medicine. The buds are seen as a sign of fertility, and are given to help mothers recover after birth. The over collection of these buds has not helped with conservation efforts but further drastically reduced the number of Rafflesia in the wild, accentuating the problem the alarmingly fast transformation of jungles into palm oil plantation creates (Sabah Travel Guide, 2004). The Rafflesia is a delicate plant that relies on an intact environment and as such is naturally extremely vulnerable to deforestation and development.
Conservation must be done to protect this species from extinct. The expert system may help the user to identify the Rafflesia species in Malaysia. By using an expert system, the user may gather information about approaches to conserve the Rafflesia.
1.3 RESEARCH OBJECTIVES
There are some purposes for this research. The main objectives of this research are:
- to identify the Rafflesia species in Malaysia based on their physical characteristics.
- to develop an expert system which help the public to recognize the Rafflesia species in Malaysia.
- to verify system performance in order to make it applicable to the real world.
1.4 SCOPE OF STUDY
The scope of this research is mainly about the Rafflesia flower and the approaches to conserve it. This research also about the system named an expert system which using Macromedia Dreamweaver 8. The system is the tool or mechanism which contains all collected information, recommendation and opinion from many expertises and also results from so many researches done. The target users of this system are tourists, publics, nature lovers and also those who interested in conserving the Rafflesia plant.
The system that will be developed will provide the public about the Rafflesia species in Malaysia as well as the approaches to conserve the Rafflesia. By using an expert system, it would easier the public to access about this endangered plant.
1.5 THESIS ORGANIZATION
This thesis consist of five chapters; introduction, literature review, methodology, results and discussion and conclusion.
Chapter 2 is about literature review. This chapter includes the Rafflesia characteristics, the diversity and habitat of Rafflesia, identification of Rafflesia species as well as treats and conservation of Rafflesia. Introduction of expert system also included in this chapter. Expert systems typically have three basic components; a knowledge base, an inference engine and user interface.
Chapter 3 is about methodology. This chapter contains the development stage of expert system for Rafflesia species identification. There are five stages in developing an expert system which are task analysis, knowledge acquisition process, prototype development, expansion and refinement and lastly verification and validation.
Chapter 4 is about the result and discussion. This chapter consists of the architecture of the system and also the flow in the developing system process. This research is using an IF-THEN rule in form of asking question to the user.
Chapter 5 is about the conclusion. This chapter consists of conclusion for overall of this research. It includes the expert system technology, the prototype development of expert system and the recommendation to make the system move effective and also ways to improve it.
The Rafflesia is one of the most magnificent flowers ever known to the botanical world. It is such a big flower with odd appearance, exceptional, rare and also mysterious. It is also immense scientific and public interest. Rafflesia in bloom has been described as simply awesome (Nais, 2001). This chapter will discuss about Rafflesia characteristics, diversity, habitat, species identification as well as treats and conservation of Rafflesia.
2.2 RAFFLESIA CHARACTERISTICS
In general, Rafflesia flowers consist of five leathery petals that are orange in colour and mottled with cream-coloured warts (Attenborough, 1995). The flower also has no leaves, stem or roots.
The dramatic Rafflesia flowers are the largest single flowers in the world; the leathery petals can reach over 90 centimetres across (Attenborough, 1995). Rafflesia is a parasite that depends completely upon its host which supplies nutrients and water to the flower. These host plants are vines of Tetrastigma spp., and the Rafflesia plant is itself not visible until the reproduction stage when flowers first bud through the woody vine and then open into the magnificent spectacle that is world-renowned today (Nais, 2001).
Most flowers in the genus give off and smell of rotting flesh, hence the local called it the “corpse flower”. When in bloom, the flower displays its five fleshy ‘petals’ or so called perigone lobes. The diameter of the various species of Rafflesia flower ranges from approximately 20 cm to a record diameter of 106.7 cm (Meijer, 1985). Other than that, the unique part of this giant flower is the flowers can take up to ten months to develop from the first visible bud to the open bloom, which may last from 5 to 7 days only.
Currently 17 species of Rafflesia are recognised and these mainly differ in the morphology of their flowers (Nais, 2001). There is a deep well in the centre of the flower containing a central raised disc raised that supports many vertical spines (Attenborough, 1995). The sexual organs are located beneath the rim of the disk, and male and female flowers are separate (Attenborough, 1995).
2.3 RAFFLESIA DIVERSITY
There are 23 completely known species and 4 incompletely known species of Rafflesia as recognized by Meijer on 1997. Table 3.1 shows the known species of Rafflesia and Table 3.2 shows the unknown species of Rafflesia as recognized by Meijer on 1997.
2.4 RAFFLESIA HABITAT
Rafflesia is restricted to the western part of the phytogeographical region of Malesia, which is known as the Sunda shelf (Nais, 2001). The region is floristically distinct, with a clear boundary from surrounding region (Steenis, 1950). Table 2.3 shows the genus distribution in their landmass location. Number in parentheses denotes the number of Rafflesia species present in each area.
Book of Rafflesia Magnificent Flower of Sabah by Kamarudin Mat Saleh (1991)
A total of 23 names of Rafflesia species have been published between 1821 and 1988 (index Kewensis, 1994). Six of the names are now considered synonyms, and a further four have inadequate type material and are treated as insufficiently known species (Meijer, 1997).
The western most extension of Rafflesia is Acheh District, Sumatra, followed by the Ranong Province in Thailand, about 5 km from the Myanmar border (Meijer & Elliot, 1990; Banziger, 1991; Elliot, 1991; Banziger et al., 1993). The eastern limit is Mount Apo Timur and at Gunung Dadum in Eastern Sabah (Nais, 2001). The northern most limits are at Mount Makiling, Los Banos Province, on Luzon Island in the Philippnes (Madulid & Agoo, 1996), and the southern limit is the province of Java, Indonesia. The distribution of Rafflesia’s genus is shown in Figure 2.1.
2.5 IDENTIFICATION OF RAFFLESIA SPECIES
The first description of the morphology of Rafflesia was made by Robert Brown (1821, 1835), who provided a detailed and meticulous description and illustrations of the male and female flowers of Rafflesia arnoldii (Nais, 2001). The taxonomy of Rafflesia is based entirely on the floral morphology (form and structure) of the flower with most emphasis on the outer appearance. The current species delimitation of Rafflesia is based on eight major characters. These eight variable characters are listed below (Nais, 2001) and the radial section of Rafflesia flower drawn by Yong Ket Hyun, after Meijer 1985 are shown in Figure 2.2.
- Size (diameter of open flowers varies from 15 cm in R. manillana to nearly 1 m in R. arnoldii);
- Diameter of the diaphragm aperture (ranging form 3-9 cm in R. micropylora, to about 20 cm in R. arnoldii);
- Number of disk processes (from none in R. rochussenii to 20-60 in R. arnoldii);
- Size and number of white spots (called blots, specks or warts) on the perigone lobes and diaphragm (from few to large in R. hasseltii to numerous and small in R. arnoldii);
- Number and size of the ‘windows’ on the inside or lower surface of the diaphragm (3-5 rings of round spots in R. micropylora, seven rings of round spots in R. kerrii, or five rings of elongate oval spots in R. pricei)
- Number of anthers (from about 15 in R. manillana to 40 in R. arnoldii);
- Structure and length of ramenta, and position of their occurrence (from short and more or less postulate in R. manillana to up to 12 mm long in R. micropylora; in R. schadenbergiana, ramenta occur on the undersite of the diaphragm; ramenta in various species may have apices branched or unbranched, swollen or crateriform); and
Number of annuli at the base of the perigone tube and column, all species has either 1 or 2
- (for example, 2 in R. pricei).
In this research, the focus is on the Rafflesia species in Sabah, Sarawak and Peninsular Malaysia only. There are eight species of Rafflesia can be found around Malaysia which is four species (R. azlanii, R. cantleyi, R. hasseltii and R. kerrii) located in Peninsular Malaysia, three species (R. tengku-adlinii, R. keithi and R. pricei) can be found in Sabah and four species (R. tuan-mudae, R. pricei and R. keithii) in Sarawak.
2.5.1 Rafflesia cantleyi Solms-Laubach
Rafflesia cantleyi was named after M. Cantley, curator of the Singapore Botanic Gardens in 1880 to 1886, who collected the type specimen in 1881. This species was described by H. Graft Solms-Laubach based on a collection made by M. Cantley in 1881. Rafflesia cantleyi has open flower dimension from 30 to 55 cm in diameter. Its perigone lobes are up to 14 cm long and 18 cm wide. It has 6 to 8 whitish warts in radial and lateral directions, about 10 in the basal row. The diaphragm opening is 4 to 8 cm across and rounded shape or sometimes angular. It has 5 concentric rings of oval white blots. Its ramenta is 2 cm long in upper type while middle and lower type is 10 to 12 mm longs, or sometimes branched, almost all with swollen apices. Its number of anthers is from 20 to 25 and this species can be found in Peninsular Malaysia only (Perak, Kedah, Perlis, Selangor, Kelantan, Terengganu, Pahang and Tioman Island). Figure 2.3 shows the picture of Rafflesia cantleyi.
2.5.2 Rafflesia hasseltii Suringar
Rafflesia hasseltii was described by Suringer in 1879 from discovery in Central Sumatra. R. hasseltii has an open flower dimension from 35 to 50 cm in diameter. It has 10 to 13 cm long and 14 to 17 cm wide of perigone lobes. It has whitish-pinkish blots across and large size of blots ranging from 5 x 3 to 10 x 1 cm. The clear contrast of snow white blots on bright brick-red background easily distinguishes this species from others. Its window is whitish or pale yellowish with a dark brown zone near the rim and the compound ramenta near the attachment point of the diaphragm gradually become white blots (window) on the lower part of the diaphragm. The R. hasseltii ramenta’s upper type is toadstool-like compound ramenta which gradually becoming the white blots of the windows. While for middle and lower type is generally linear with swollen apices. The number of anthers is 20 and this species can be found in Sumatra, Peninsular Malaysia and Borneo and its altitudinal distribution is from 400 to 600 m. Figure 2.4 shows the picture of Rafflesia hasseltii.
2.5.3 Rafflesia keithii Meijer
Rafflesia keithii was named after Harry G. Keith, the former Conservator of Forests in British North Borneo or nowadays called Sabah, Malaysia. This species was described by Willem Meijer in 1984. Rafflesia keithii has an open flower dimension from 80 to 94 cm in diameter. The perigone lobes are 10 to 12 cm across at the median of the lobes but sometimes it has six-lobed. Its colour is numerous white warts with dense, more or less of the same sizes. The diaphragm opening is normally 5 concentric of white warts in about 40 radial rows, each surrounded by a dark red-brown margin. Its window has 5 to 6 rings of large, white blots, those nearer to the rim merging. The ramenta for upper type is 5 to 6 mm long which often fascicled (in bundles) middle and for lower type is solitary and only some with a swollen head. Rafflesia keithii always has 40 numbers of anthers. This species can be found only in Borneo with 250 to 940 m of altitudinal distribution. Figure 2.5 shows the picture of Rafflesia keithii.
2.5.4 Rafflesia kerrii Meijer
Rafflesia kerrii was named after A.F.G. Kerr, Thailand’s first Government Botanist, who collected the specimen from which the specimen was described. This species was described by Willem Meijer in 1984. Rafflesia kerrii has an open flower dimension of 50 to 70 cm in diameter. It has 13 to 20 cm long and 19 to 24 cm wide of perigone lobes. Its colour is dull red with brownish tinge and have numerous and scattered warts with 3 to 4 mm space between them. The size of warts for R. kerrii is the smallest compared to other species. The diaphragm opening ia about 12 to 17 cm across and have upper face with 3 to 4 concentric rings of white spots surrounded by a dark red margin. The characteristics for its window are bright white in colour with roundish to elliptic blots and up to 10 mm of diameter. This species of Rafflesia has ramenta that mostly unbranched and only slightly swollen at apex. Its anthers consist of about 26 to 31. The distribution of Rafflesia kerrii is surrounding Thailand and Peninsular Malaysia which at attitude from 500 to 1000 m. Figure 2.6 shows the picture of Rafflesia kerrii.
2.5.5 Rafflesia pricei Meijer
Rafflesia pricei was named after William Price, a honourary plant collector for the Royal Botanic Garden, Kew, who collected this species along the trail to the Mamut Copper Mine. This species of Rafflesia was described by Willem Meijer in 1984. Rafflesia pricei can only be found in Sabah only. It has 16 to 45 cm of opening flower dimension. It has 40 to 80 raised whitish spots (warts) surrounded by brick-red background. The spots range from 1 to 4 cm in length and the surface is minutely rugolose giving a matted appearance while the red background is densely papillose (Beaman at al., 1988). The diaphragm opening is about 5 to 6 cm in diameter and the diaphragm has 4 to 5 irregular rings of white spots smaller than those of the perigone lobes, surrounded by brick-red areas that grade into the cream-white background, the inner edge has a narrow white margin with a continuous reddish-brown area just outside the white rim (Beaman et al., 1988). The R. pricei has 4 to 5 concentric rings of large white window panes or blots and contracting with the bright red background. The interior of the perigone tube from the base of the tube to the lower edge of the diaphragm is lines with wine-red ramenta. The upper type (near the diaphragm’s opening) is about 2 to 6 long while middle type (near the insertion of the perigone lobes) is about 4 to 6 cm long and the lower type (near the base of the perigone tube) is about 6 to 7 mm long. The number of anthers for R. pricei is 20. Figure 2.6 shows the picture of Rafflesia pricei.
2.5.6 Rafflesia tengku-adlinii Mat Salleh & Latiff
Rafflesia tengku-adlini was named after Tengku Datuk (Dr.) Adlin Tengku Zainal Abidin, a keen naturalist and conservationist in Sabah who facilitated the documentation of the species after its recovery. This species was described by Kamarudin Mat Salleh and A. Latiff Mohamed from a specimen collected at Mount Trus Madi, Sabah in the year of 1989. R. tengku-adlinii is endemic species to Sabah only at altitude 610 to 800 m. Its opening flower dimension is about 20 to 25 cm diameter while its perigone lobes are 7 to 12 cm long and 12 to 16 cm wide. The colour of R. tengku-adlinii is bright to dull orange throughout with warts throughout the upper surface except near the diaphragm opening. The diaphragm opening is up to 12.5 cm wide and about 3 cm in diameter. It has no windows and the lower diaphragm covered with ramenta. The ramenta occurs right up to the opening of the diaphragm with 3 to 5 cm long, apices swollen, upper, middle and lower types all have fine bristles. The number of anthers for this species is 20. Figure 2.8 shows the picture of Rafflesia tengku-adlinii.
2.5.7 Rafflesia tuan-mudae Beccari
Rafflesia tuan-mudae was named after Mr. Carlo (Charles) Brooke Tuan Muda of Sarawak. This species wasfirst collected from Mount Pueh, Sarawak, from which specimen the species was described by Beccari in 1868. Rafflesia tuan-mudae also is an endemic species. It only can be found in Sarawak. The opening flower dimension can reach from 44 to 92 cm in diameter. The numbers of perigone lobes is usually 5, sometimes 6 (at Gunung Gading National Park, Sarawak (personal observation), or even 7 (in Cagar Alam Gunung Raya Pasi (Zuhud et al., 1998). The colour of R. tuan-mudae is much like R. keithii, but it only has 5 to 8 warts across the median. The diaphragm opening is from 15 to 18 cm and the number of anthers is unknown. Figure 2.9 shows the picture of Rafflesia tuan-mudae.
2.5.8 Rafflesia azlanii Latiff & M. Wong
Rafflesia azlanii is endemic species to Peninsular Malaysia only at altitude 150 to 400 m. Its opening flower dimension is about 38 to 50 cm diameter while its perigone lobes are 9.5 to 10.5 cm long and 12 to 14.5 cm wide. The colour and pattern of R. azlanii is large and continuous (not all like R. hasseltii) whitish warts with brick-red background. The diaphragm opening is from 4.7 to 5.5 cm in diameter. During an early stage of blooming, the open diaphragm is about 7 cm and when the flower bloom fully, the open diaphragm become wider up to 18 cm. The flower’s window is large whitish scattered of warts. The ramenta for upper type is 6 mm long while for lower type is 4 mm long. The number of anthers for this species is unknown. Figure 2.10 shows the picture of Rafflesia azlanii.
2.6 THREATS AND CONSERVATION
Rafflesia is one of the most threatened and also one of the rarest plants in the world. The existence of this prodigious flower is precarious and it will eventually become extinct without active conservation efforts.
Rafflesia are inherently rare as a result of a number of factors of their life cycle; they have a double habitat specialisation, as they can only successfully parasitise particular species and these species in turn are found only in specific habitats (Nais, 2001). In addition to this factor, there is an extremely unbalanced sex ratio in the Rafflesia flowers observed, with many more male than female flowers (Nais, 2001).
Flower buds have a high level of mortality and only 10 to 18 percent go on to bloom, these only lasting for a few days; the chances of a male and female flower being in bloom at the same time in a close enough vicinity to be pollinated is therefore extremely slim (Nais, 2001). In addition to these inherent factors, there is widespread habitat destruction within much of the rain forested area of Southeast Asia and Rafflesia buds are also collected for traditional medicine to treat fertility problems, in parts of their range.
The tropical rain forest is the most threatened environment and has experienced the greatest loss of species during our lifetime (Lucas & Synge, 1981). Human disturbance is one of the factors that result great loss of this natural habitats and species. Under the present circumstances, Rafflesia appears to be one of the genera approaching extinction (Nais, 2001). Therefore, the tropical rain forest and all their inhabitants must be the main focus in conservation efforts.
2.6.3 Conservation Status of Rafflesia
The World Conservation Union, IUCN (1984, 1988, and 1997) established five main categories to highlight the conservation status of species:
- Extinct (no longer known to exist in the wild)
- Endangered (species that have a high likelihood of becoming extinct in the near future)
- Vulnerable (species that may become endangered in the near future because populations are decreasing in size throughout the range)
- Rare (species that have small total numbers of individuals, often due to limited geographical ranges or low population densities)
- Insufficiently known (species that probably belong in one of the preceding categories but are not sufficiently known to be assigned to a specific category).
The conservation status of Rafflesia can only be reliably assessed by acquiring and analyzing extensive field data of each species. These data include the distribution and the characteristics of sites, rarity and reproductive ecology. The conservation status of all Rafflesia species based on current knowledge which is from published account recognized by IUCN (1997), present analysis using the WCMC/IUCN classification of Conservation Status and present analysis using the IUCN’s new Categories of Conservation Status are shown in Table 2.4.
2.6.4 Approaches to Conserve Rafflesia
There are two approaches can be taken according to Nais (2001). One of the approaches and also the best conservation approach for any species is in situ (or on site) conservation which mean leaving it to grow wild in its original habitat. In situ conservation is usually more effective than other approaches because natural condition often impossible to duplicate artificially. In situ conservation strategy of Rafflesia involves:
i) Protection inside established Conservation Areas
One of the major problem to conserve the Rafflesia is because so many tourist eager to pay homepage to existing Rafflesia sites, cause massive trampling, even to level where some populations are trampled to extinction. The mechanisms to control over-visitation are inadequate, and the infrastructure to minimize its impact is not well developed. One way to avoid trampling is by constructing boardwalks or walkways over Rafflesia population. In addition, Rafflesia sites outside conservation areas need to be made available for tourists, thus reducing the pressure for population within conservation areas (Nais, 2001).
ii) Designating New Conservation Areas
It may not be possible to make each Rafflesia site become conservation areas. A more plausible strategy is to synergize the Rafflesia cause with other issues, such as the protection of forests for water catchment, total habitat and biodiversity conservation, and also for nature tourism development (Nais, 2001). This may allow larger area to be conserved to protect their habitat and also their population.
iii) Protection of Sites in other Areas
Many Rafflsia locations are outside the protected areas which within the land belong to the indigenous community. Cooperation from the landlords is very important in order to conserve the Rafflesia. By doing opening sites for tourism is one viable conservation solution and apart from that, it also can generate income for the landowners.
The second approach is by doing ex situ conservation. Ex situ conservation (sometimes referred to as ‘off-site’ conservation) is the conservation of plants away from their natural occurrence [Given (1994) cited in Nais (2001)]. This approach includes conserving whole plants or plants in botanical garden and gene banks, as well as using laboratory techniques such as tissues culture for their propagation and preservation. Bringing Rafflesia into cultivation has always been appealing. Its cultivation would important not only for its conservation, but also as an important step towards utilization of the plants for ecotourism purposes (Nais, 2001).
Prior to the success by Nais et al. (in press, 2000), many researchers had unsuccessfully tried various methods and techniques of ex situ propagation of Rafflesia. These attempts have included efforts to grow Rafflesia by way of seed insertion into host plants and the translocating of Tetrastigma plants with Rafflesia buds (Nais, 1997; Nais & Wilcock, 1999). Similar cattempts conducted by various other people have also not been successful, for example: seed germination, tissues culture of Rafflesia and grafting of infected host plants into uninfected ones (Ghazally, 1991; Latif & Mat-Salleh, 1991; Zuhud et al., 1998). These failures have initially led some researchers to believe that ex situ cultivation possibly may never be a viable option for the conservation of Rafflesia species (Meijer, 1997) until Nais et al. achieve successful in 1999.
2.7 EXPERT SYSTEM AS A SOLUTION
Artificial Intelligence (AI) is a branch of computer science that is principally concerned with using computational models to understand how humans think (Tanimoto, 1987). Major research areas include expert systems, search methods, knowledge representation, logical and probabilistic reasoning, learning, natural language understanding, vision, and robotics (Cohen and Feigenbaum, 1982).
The most successful application of Artificial Intelligence so far is the development of Decision Support System (DSS), particularly expert system, which is a computer program that act as a ‘consultant’ or ‘advisor’ to decision makers (Generation5, 2005).
According to Turban & Aronson (2001), an expert system is a system that uses human knowledge captured in a computer to solve problems that ordinarily require human expertise, or, a computer program that can solve problems in a specific area of knowledge (the problem domain) as well as a human expert (O’Keefe et al., 1987), or, that automates tasks that are normally performed by specially trained or talented people (Shannon et al., 1985). Usually when an organization having problem to solve and have to make critical decision, they often turn to consultants or experts seeking for advice. These experts or consultants have specific knowledge and experience in the problem area. They are aware of alternative solutions, chances of success, and costs that the organization may incur if the problem is not solved. Experts can diagnose problems correctly and solve them satisfactorily within a reasonable time frame.However, human experts are expensive, and they may not be readily available.
Expert systems are an attempt to mimic human experts (Turban, Rainer, & Potter, 2001). The expert system begins by asking questions about the problem to be solved. When the needed information has been gathered (inputted by user), the system offers suggestions about how the problem can be solved (McEneaney, 1992). According to Wentworth (1993), expert systems differ from conventional programs in the way they store and use information. In a conventional program, the operations never vary as the programmer predetermines them. The conventional program contains precisely defined logical formulas and data, and if any data element is missing, the program will not run. The expert system, like the human expert, contains heuristic information and can function with incomplete information.
2.7.1 Components of Expert System
An expert system is typically composed of at least three primary components. These are the inference engine, the knowledge base, and the working memory (Wikibooks, 2010). An expert system, also known as knowledge-based system, uses the knowledge and experience of experts to solve problems in a reasonable period of time. Human experts solve problems by using their factual knowledge and reasoning ability. In the other hand, an expert system uses its knowledge base and inference engine to perform a similar task. Figure 2.1 shows the main components in an expert system.
The knowledge base supplies specific facts and rules regarding a domain, while the inference engine offers the reasoning ability that allows the expert system to make conclusions. The user interface is the medium between the expert system and the user. An expert is someone who has the ability to achieve a specific task efficiently by using his or her skills, experience, and knowledge in a specific domain.
188.8.131.52 Knowledge Base
Expert systems are based on human knowledge and reasoning patterns (Wikibooks, 2010). The knowledge base an expert uses is what he learned at school, from colleagues, and from years of experience. The more experience he has, the larger his store of knowledge. Knowledge allows him to interpret the information in his databases to advantage in diagnosis, design, and analysis (Edward and Robert, 1993). This knowledge must be extracted from a human expert by a specialized knowledge engineer. Knowledge engineers ask the expert questions about his knowledge and his reasoning processes, and attempts to translate that into
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