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Semantic Technologies as Enabler
Published in Sarika Jain, Understanding Semantics-Based Decision Support, 2021
Jess: The Java Expert System Shell (Jess) came along when Java was very young. Jess is a fully developed Java API inspired by CLIPS for building rule-based expert systems. It uses an improved form of the Rete (Latin for “net”) algorithm to match patterns, i.e., facts in the knowledge base, to rules in the rule base. Jess has a Lisp-like syntax and is quite easy to learn and use. The rules can be written in two formats, XML or the Jess rule language, with the latter preferred. The central concept in Jess is forward chaining. Only developers type on a console; the command line is not intended for end users. Jess is about acting in response to inputs, not only answering queries. It uses forward chaining and the Rete algorithm, so the working memory must be populated with all relevant facts before execution of rules; this is not the case with SWRL, because of backward chaining. An example of Jess rule follows:
Introduction to Expert Systems
Published in Chris Nikolopoulos, Expert Systems, 1997
General production system languages include OPS5 and CLIPS. Object oriented production systems environments have also become available, like COOL (object oriented extension of CLIPS) and JESS. JESS (Java Expert System Shell) is written in SUN's Java language and it further extends the features of CLIPS by providing the ability to use scripting applets and interface with the Web. OPS5 is a general production systems language, which has been used to implement a number of large expert systems. It was originally developed in conjunction with the R1/XCON expert system used by DEC to configure computers. In OPS5, a time tag is associated with each working memory element. The time tag indicates when the element was last modified or added into the working memory. The larger the time tag, the more recent the element. Time tags are used by the conflict resolution strategy. The programmer has a choice of two conflict resolution strategies, LEX and MEA, which are based on the recency of matching facts (time tags) and generality of rule conditions. LEX is simpler than MEA, while MEA provides more execution control than LEX. CLIPS, which is written in C, was developed by NASA and is similar to OPS5.
Backward chaining inference as a database stored procedure – the experiments on real-world knowledge bases
Published in Journal of Information and Telecommunication, 2018
Tomasz Xie¸ski, Roman Simiński
The knowledge-based systems were typically developed as desktop applications. Meanwhile, web applications have grown rapidly and have had a significant impact on the application of a traditional expert system. The detailed discussion and comparison of modern knowledge-based systems building tools go beyond the scope of this study. Selected aspects of such review can be found in Ruiz-Mezcua et al. (2011) and Mathkour et al. (2009) and also in Grove (2000), Duan et al. (2005) and Huntington (2000). In this work only a basic overview is presented. The JESS is a well-known and popular tool. It is the skeleton of expert systems developed by Sandia National Laboratories. JESS is written in Java and it is possible to run code in this language using JESS. It uses a syntax similar to Lisp (JESS, 2016). It is compatible with both Windows and Unix systems. Rules written using JESS are saved in the form of an XML file which must contain a rule-execution-set element (Canadas et al., 2010). JESS is a rule engine as well as a scripting language, which provides a console for programming and enables basic input/output operations. JESS is a forward chaining inference engine, it provides mechanisms that ‘simulate’ backward chaining.
Relationship between UAVs and Ambient objects with threat situational awareness through grid map-based ontology reasoning
Published in International Journal of Computers and Applications, 2022
Myung-Joong Jeon, Hyun-Kyu Park, Batselem Jagvaral, Hyung-Sik Yoon, Yun-Geun Kim, Young-Tack Park
Jess is a rule engine and scripting environment written using Java language. It can build the Java software, which has the capacity to reason using knowledge in the form of declarative rules. Jess is intuitive and light, and it is useful for building applications because it can be used with full java APIs. Jess uses the Rete algorithm to process rules. Rete is optimized to solve many-to-many matching problems effectively.