Embedded Systems Applications - Essay Example

Embedded Systems Applications Introduction An embedded network system is a system that consists of a number of embedded units that are able to communicate with each other. Embedded systems have become more connected and they have become very crucial communication channels in digital systems. This results in a large scaled complicated network system. In this research paper, we are going to concentrate on creating a methodology for a high-speed radio frequency system, preparing documentation for the implemented system, perform a test strategy and finally evaluate the performance of the system. Methodology The target system in this research is an embedded network system that produces the necessary data for manufacture of a high-speed radio identification system. This can be considered as a concurrent system that may consist of a number of sub systems that has a number of global environments. Such environments may include both an embedded indoor and outdoor equipment. Each of the available sub systems is triggered by the prevailing events and the operations are usually controlled by the presiding conditions. The general flow of information can be represented as shown below: Figure 1: general flow of information in the embedded system The way in which the behavior of the embedded system is specified can be termed as being hierarchical in nature. Such a system has subsystems that are constructed from the existing functions. In order to enhance the reliability and efficiency of the design of the system, the following tasks will be done: 1. Specification of the requirements: For the air condition system, the original specific documents written in a natural language are translated into formal specifications in a language that conforms to the embedded network systems. 2. The embedded network systems specifications are translated to conjunctive normal form formulas in accordance with the translating rules. 3. The conjunctive normal form formulas are solved using the existing solver. 4. Mapping from assignments to test cases. 5. Generating test sequences under a testing goal. In order to complete the task at hand successfully, we use a language that is referred to as MC51 which is represented by logical formulas and is based on a quantifier free predicate. It has the following features: a) The language is based on the existing properties. b) The language is test oriented. c) The language is object oriented. d) The language is modular in nature. e) The language supports the lightweight description of time constraint. Figure 2: Flowchart diagram for the embedded system The pseudo code used for the implementation of the system is shown below. Import  A,  B; Class  main Data On off_status  {on,off}; Var B1,  B2 : B; A1 : A(B1,  B2); Import B; Extern Data onoff_status;  //from  main Class  A(arg1 : B,  arg2 : B) Var op : onoff_status {off}; Timer t 4 sec;   Function SendingM Require ~op==off && op==on : null: t!start; op==on : t?ring : arg1.ch!m,arg2.ch!m; Extern   Data      onoff_status; //from main Class B Data m_type {m}; Var   op : onoff_status {off};      lamp : onoff_status {off}; Channel    ch : m_type; Function Lighting Require   op==on/wet && lamp==off : ch?m:lamp==on;      op==off −> lamp==off; Program description a) Declaration of the main class: File   is used to specify the main class. This is used to represent the entire system that consists of all the subsystems in the current environment in which the system is built for.inn the pseudo code, the classes are imported and the sub systems are then put in instantiation during the implementation of the program. The environment variables are also declared in the main class. b) Declaration of classes: this is shown by the Files   and  . They are used to specify the classes of a sub system. Different types of data types, different variables, and the existing system timers are declared in the declaration of each of the existing classes. c) Declaration of variables and data types: variables are usually declared with the name, the type, the initial values of the variables and the existing values and bounds for tests. Data types can be in the form of integers, doubles and other enumerate data types such as strings. d) Declaration of the timers and the existing channels: The importance of having channels in the pseudo code is to be able to provide a description of the communication between the sub systems. A channel is usually declared using the name allocated to it and the type of message it conveys. A timer, on the other hand, is declared using a name, the value of the time unit and the existing counting conditions. e) Declaration of functions and requirements: when the classes are being declared, the functions are also defined and this involves the declaration of constants, data types, variables, variables and any existing timers. Requirements are also contained within the functions. They usually represent an invariant or an event. Testing Strategy This will be achieved using the SAT solver. This tool is used to solve the SAT problem and this is used to determine whether there is a value assigned to satisfy a given Boolean formula in Conjunctive normal form. In the existing system, we already have a target system that is well described. There is, therefore, the need to have a model that satisfies all the specifications. Each of the transitions in the model corresponds to a one step test case. These include: 1. Prostate for the input. 2. Valid input state. 3. Posted for the output. Translation of the MC51 to Conjunctive Normal Form All the existing requirements are translated to Conjunctive Normal Form formula and this becomes an input to the SAT solver. Using the already set conditions and specifications, the requirements can then be translated into Conjunctive Normal Form. Translation entails three main steps: a) Introduction of fresh propositional variables and this helps to construct state space of the system model. b) Transition requirements and invariants c) Collection of all the constraints that are presented in logical formulas. These are connected with conjunctions and the result is converted to Conjunctive Normal Form. Generation of the test cases After the generation of the Conjunctive Normal Form formula, we can then apply the SAT solver to the in order to obtain the assignment. This makes the set requirements to be true and thus correspond to the test case. Below is the algorithm that was used to generate the test cases. The SAT solver was used to explore all the possible assignments and they are then converted to test cases. Data: An MC51 specification  Result: A Set of test cases begin Translate the given MC51 specification to a logical formula in conjunctive normal form; Input into a SAT solver; if   is  satisfiable then The SAT solver can output a solution corresponding to one test case; Add the solution to a set of existing solutions; Let and then return Step 2 to search for an alternative solution; else The SAT solver declares is not satisfiable; This means there are no more solutions; The previous solutions are translated to test cases and then stopped; Finally, return the set of test cases; Filtering The methods that are in use are capable of generating a wide coverage for the requirements of any given specification. The filtering technique can be used to extract the most efficient test cases that satisfy the existing pre conditions and post conditions. Evaluation of the design From the design above of the embedded system, the following weaknesses can be identified: 1. There is an existing challenge in constructing a real time system that incorporates both real times in terms of both time and output. 2. The test generator may not have the capacity to deal with and handle the compositions of the subsystems. In order to make the system more efficient, a number of measures can be proposed to make improve the system. 1. Improve the methods of automatic test generator test sequences so that they are obtained automatically based on a testing goal. This can be achieved by use of TGSENS to improve the quality of the embedded system. 2. The use of scalable test generators can also improve the performance of the system. 3. The application of model checking techniques. Conclusion From the discussions above, the design of an embedded system calls for a sequential creation of a model that creates a model using programming languages such as MC51 and then testing it before implementation. This has been achieved and from the results of the test case, the system can be improved in any way seen appropriate. References Harel, D. Statecharts: A Visual Formalism for Complex Systems. The Science of Computer Programming, vol.8, no.3, pp. 231-274. Glinz, M. An Integrated Formal Model of Scenarios Based on Statecharts. In Proceedings of the 5th European Software Engineering Conference (ESEC 95), Sitges, Spain, 1995, pp. 254-271. Koskimies, K., T. Systä, J. Tuomi, and T. Männistö. Automated Support for Modeling OO Software. IEEE Software, vol.15, no.1, 1998, pp. 87-94. Systä, T. Incremental Construction of Dynamic Models for Object-Oriented Software Systems. Journal of Object-Oriented Programming, vol.13, no.5, 2000, pp. 18-27. Louden, K. 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