Expert System for Diagnosis of Pepper Plant Diseases Using Certainty Factor and Naïve Bayes Methods

Development expert system for diagnosis of pepper plant diseases using certainty factor and naïve bayes methods. Pepper is one type of plant that has long been traded on the European market. So that increasing the quality and quantity of pepper production is the main demand. However, diseases in pepper plants are also familiar to be found so that they can be detrimental to farmers and besides that, agricultural workers who are experts in the field of pepper plant diseases are still limited. Therefore, to overcome this problem, an expert system application is designed where this system can provide information about diseases that attack pepper plants, then provide suggestions or solutions to deal with these diseases. The purpose of this research is to build and design an expert system that is useful for determining pepper plant diseases and to apply certainty factor and nave Bayes methods in providing answers to the results of the consultation. The results of this study are expected to make it easier for users, especially farmers or farm workers in overcoming diseases in pepper plants. Keywords— Certainty Factor, Nave Bayes, Pepper Plant Disease


I. INTRODUCTION
Pepper is one type of plant that has been cultivated for a long time and the results have also been traded on the European market for a long time. So that the pepper trade in Indonesia was finally recognized throughout the world. Pepper is a spice plant. More than 80% of pepper production in Indonesia is an export commodity. To compete in the world market, increasing the quality and quantity of pepper production is a major demand.
Diseases in pepper plants are also familiar to farmers. But sometimes not all farmers know that the disease can be harmful or not. And also they only know that the plant is attacked by disease but do not know what disease is attacking to cause crop failure.
However, in the current era of globalization, we do not need to worry because technology has an important role in society. All activities are currently carried out with various technologies that are increasingly sophisticated and continue to grow rapidly, one of which is computer technology. With this progress, it will facilitate all community activities, especially in the field of agriculture by providing software, for example, an expert system in the form of a program designed to find out various types of diseases in plants (Munif & Sulistiawati, 2014) Based on the description of the problem, the authors decided to take the title "Expert System for Disease Diagnosis in Pepper Plants Using Certainty Factor Methods and Web-Based Naïve Bayes" in writing this study.
The formulation of the problem taken from the background described above is how to design a web-based Expert System to diagnose diseases in pepper plants using the Certainty Factor and Naive Bayes methods and how to implement the Certainty Factor and Naïve Bayes methods into an expert system so that it can provide conclusions to determine types of diseases in pepper plants.
So that the discussion of the problem does not widen, the authors limit the problem into several parts, namely this expert system is built based on WEB, the method used to diagnose diseases in pepper plants uses the Certainty Factor and Naïve Bayes methods, the output produced is the result of disease diagnosis in pepper plants from experts and the final result of this study is a comparison between 2 methods, namely Certainty Factor and Naive Bayes.
The purpose of making this expert system is to build and design an expert system that is useful for diagnosing diseases in pepper plants, applying certainty factor and nave Bayes methods in providing good answers and conclusions.
And for the expected results in making this expert system, among others, helping farmers in determining diseases that attack pepper plants easily, quickly, precisely, and accurately and as input and information on how to overcome when pepper plants are affected by the disease. TEPIAN Vol. 2 No. 4 (December 2021) p-ISSN 2721-5350 e-ISSN 2721-5369 Karmila, Maria, E., & Annafi' Franz. (2021)

A. Study of Literature
Some of the literature used as a guide and reference in the preparation of this research include: 1. In the research of (Hariyanto & Sa'diyah, 2018) entitled "Expert System for Diagnosing Joint Disease Using the Certainty Factor Method". In the world of health, diagnosing a disease is a very difficult thing to do and so are the symptoms of a patient's disease recorded in the medical record, for example in the problem of diagnosing joint diseases such as the relationship between bones called joints. 2. In the study of (Yuliyana & Sinaga, 2019) entitled "Expert System for Diagnosis of Dental Diseases Using the Naive Bayes Method". Some of the problems that arise when suffering from a toothache, patients do not have much time to identify the cause of toothache, medical treatment steps require more time to consult a dentist. Expert systems are here to be helpers or assistants who will guide someone to solve problems with the support of expert data stored in the computer 3. In the study of (Tosa et al., 2020) (Ferdiansyah et al., 2018) entitled "Expert System for Diseases in Goats Using the Naïve Bayes Method and Certainty Factor". Disease checks on goats regularly are currently not getting enough attention, making goats susceptible to disease. This makes it difficult for farmers in the initial handling and does not know what to do without an expert. 5. In the study of (Syahrawardi et al., 2018) entitled "Expert System for Diagnosing Pests-Diseases in Sweet Night Plants Using the Android-Based Naïve Bayes-Certainty Factor Method". The production level of tuberose is still low because the seeds used are still careless and pests and diseases attack so that it has an impact on the productivity and quality of flowers. There are various kinds of pests and diseases on tuberose plants that can cause minor damage to crop failure. 6. In the study of (Sihotang, 2019) entitled " Expert System To Diagnose Diseases In Corn Plants With Bayes Method ".The many diseases in corn today can make farmers confused in determining or choosing the type of treatment that suits the corn disease. This makes it difficult for farmers to get results because they cannot make the right diagnosis so that productivity levels decline.
Computer-based expert systems can be used to help solve problems in terms of helping each farmer in determining treatment options. The method used in diagnosing diseases in corn is the Bayes method, where each alternative provided will be ranked to obtain the best results. 7. In the study of (Rositasari et al., 2018) entitled "Implementation of Naive Bayes with Certainty Factor for Dog Disease Diagnosis ".The dog disease diagnosis system was created to assist the work of veterinarians in diagnosing canine diseases, besides that this system is expected to assist the public in making an initial diagnosis of their pet dogs that are infected with the disease. This system applies the Naïve Bayes and Certainty Factor methods based on Android. The Naïve Bayes method is used to classify dog diseases based on the pattern of symptoms that are commonly experienced, while the Certainty Factor method is used to determine the certainty value of the classification results from the Naïve Bayes method.

B. Expert System
Expert system (expert system) is a branch of Artificial Intelligence (AI) that is quite old because this system was developed in the mid-1960s. The expert system that first appeared as the General-purpose problem solver (GPS) was developed by Newell and Simon. The term expert system comes from the term knowledge-based expert system. This term arises because to solve problems, Expert Systems use the knowledge of an expert that is entered into the computer. Someone who is not an expert uses the Expert System for a knowledge assistant. Expert system is a system that uses human knowledge where the knowledge is entered into a computer and then used to solve problems that usually require human expertise or expertise (Mulyani & Komarudin, 2020)

C. Pepper Plant
Pepper plant (Piper nigrum L.) belongs to the spice and medicinal plant group is an annual climbing plant that is morphologically classified as a dimorphic plant that has two main parts, namely tendrils (hanging tendrils and climbing vines) and lateral branches as a place for the discharge of flowers and flowers. fruit. Pepper plants obtained by fruit branch cuttings will produce shrubshaped plants and only have fruit branches (phototropic positive). While pepper plants obtained by climbing vine cuttings will produce plants that have climbing vines and fruit branches The following are some types of diseases that often attack pepper plants that pepper farmers must know : 1. Root rot disease The typical symptom of this disease is a blueblack color at the base of the stem which is accompanied by the formation of mucus. Attacks on leaves cause stamping symptoms in the center or edges of the leaves. The edges of the black spots are jagged like lace, which are visible when the symptoms are still fresh and do not appear when the leaves have dried or in advanced symptoms.

Jaundice
Symptoms of jaundice can be seen in the crown and roots of the soil surface. The growth of the affected plants will slow down, the yellow leaves will be stiff and the roots will be damaged. Some of them also cause root cavities due to M. incognita attack.

Dwarf disease
The dwarf disease is characterized by symptoms of small, curly young leaves that are pale yellow and mottled. Fruit size is smaller than normal fruit 4. Peel Fungus Disease Symptoms that arise when the leaves dry up, then on the surface of the diseased branch or stem there is a shiny white fungal thread like a spider's web.

Marasmius Fungal Disease
The symptoms that appear are the leaves will dry and die. These dry leaves will fall and hang on the branches.

Blonde Pepper Fungus Disease
Symptoms that appear are branches or twigs covered with silvery-colored mushrooms like a crust which is a collection of fungal mycelium. The fungus forms a carpet/velvet-like layer that is initially white then becomes silvery gray and finally turns brown. The next branch or twig will dry up and die. 7. Pepper Leaf Spot Disease Symptoms that appear are pepper leaves will experience spots with variations in gray, brown, and black. Symptoms that arise from pepper root rot disease are pepper root will turn black, then it will rot and when it is moist it will appear bluish mucus.

D. Certainty Factor
Expert systems must be able to work in uncertainty. Several theories have been found to solve the problem of uncertainty, including classical probability, Bayesian probability, Zadeh fuzzy theory, and Certainty Factor.
Certainty Factor is a method to prove whether a fact is certain or uncertain in the form of a metric that is usually used in expert systems. This method is very suitable for expert systems that diagnose something uncertainty (Agus et al., 2018) Certainty factor introduces the concept of belief and uncertainty which is then formulated in the following basic (1). If all the preliminary evidence is known with certainty then the (3).

CF (E,e) = CF (H,E)
In the application, CF (H, E) is the certainty value given by the expert to a rule, while CF (E, e) is the confidence value given by the user for the phenomenon experienced. And the following table of evidence of the value of the Certainty Factor shown in the table 1. E. Naive Bayes Naive Bayes is a simple probabilistic classifier that calculates a set of probabilities by adding up the frequencies and combinations of values from a given dataset. The algorithm uses the Bayes theorem and assumes all attributes are independent or not interdependent given by the value of the class variable. Another definition says Naive Bayes is a classification with probability and statistical methods proposed by British scientist Thomas Bayes, which predicts future opportunities based on previous experience.
Naive Bayes is based on the simplifying assumption that attribute values are conditionally independent if given an output value. In other words, given the output value, the probability of observing together is the product of the individual probabilities. The general form of Bayes' Theorem can be seen in equation (4).
Description : X = data with unknown class H = data hypothesis X is a specific class P(H|X) = hypothesis probability H based on condition X (posterior probability) P(H) = hypothesis probability H (prior probability) P(X|H) = probability X based on condition on hypothesis H P(X) = probability of X

F. Black Box Testing
Black-Box Testing is a software testing technique that focuses on the functional specifications of the software. Blackbox Testing works by ignoring the control structure so that its attention is focused on domain information allowing software developers to create a set of input conditions that will train all functional requirements of a program (Kasus et al., 2018) TEPIAN Vol. 2 No. 4 (December 2021) p-ISSN 2721-5350 e-ISSN 2721-5369 Karmila, Maria, E., & Annafi' Franz. (2021). Expert System for Diagnosis of Pepper Plant Diseases Using Certainty Factor and Naïve Bayes Methods. TEPIAN, 2(4). https://doi.org/10.51967/tepian.v2i4.744 -178 -

A. Research Tools and Materials
The tools and materials that will be used in the research on the

G. Research procedure
The research procedure is a step that will be carried out by the author to make it easier to conduct research. It can be seen in picture 1.

V. CONCLUSION
The expert system application was built using the certainty factor and nave Bayes methods, it can make it easier for farmers to use information about symptoms, diseases, and controls on pepper plants.
This expert system application can provide conclusions about the diseases found in pepper plants based on the symptoms entered, then if the user selects one of the conditions Very Confident, Confident, Less Confident and Doubtful from the symptoms of the existing disease, the percentage of the selected disease will appear along with causes and solutions.