• Journal of the Korean Society of Systems Engineering
• /
• v.1 no.2
• /
• pp.43-48
• /
• 2005

This paper describes the results of applying States and Modes Analysis, one of the requirements analysis techniques, to the development requirements of flight control software for Smart UAV. State/mode table enabled us to investigate various operation and design concepts, and as a result essential requirements for flight control software were established without omitting necessary requirements. Through the use of scenario-specific state transition diagrams, dynamic behaviours and control/response interfaces between each state and mode could been clearly identified, which made it possible to establish requirements related to dynamic behaviours of states and modes which are essential to the design of flight control software.

• Nuclear Engineering and Technology
• /
• v.45 no.5
• /
• pp.637-652
• /
• 2013

Instrumentation and control systems in nuclear power plants have been digitalized for the purpose of maintenance and precise operation. This digitalization, however, brings out issues related to cyber security. In the most recent past, international standard organizations, regulatory institutes, and research institutes have performed a number of studies addressing these systems cyber security.. In order to provide information helpful to the system designers in their application of cyber security for the systems, this paper presents methods and considerations to define attack vectors in a target system, to review and select the requirements in the Regulatory Guide 5.71, and to integrate the results to identify applicable technical security control requirements. In this study, attack vectors are analyzed through the vulnerability analyses and penetration tests with a simplified safety system, and the elements of critical digital assets acting as attack vectors are identified. Among the security control requirements listed in Appendices B and C to Regulatory Guide 5.71, those that should be implemented into the systems are selected and classified in groups of technical security control requirements using the results of the attack vector analysis. For the attack vector elements of critical digital assets, all the technical security control requirements are evaluated to determine whether they are applicable and effective, and considerations in this evaluation are also discussed. The technical security control requirements in three important categories of access control, monitoring and logging, and encryption are derived and grouped according to the elements of attack vectors as results for the sample safety system.

• Journal of Astronomy and Space Sciences
• /
• v.26 no.4
• /
• pp.643-650
• /
• 2009

Korea Astronomy and Space Science Institute (KASI) has been developing one mobile and one stationary SLR system since 2008 named as ARGO-M and ARGO-F, respectively. KASI finished the step of deriving the system requirements of ARGO. The requirements include definitions and scopes of various software and hardware components which are necessary for developing the ARGO-M operation system. And the requirements define function, performance, and interface requirements. The operation system consisting of ARGO-M site, ARGO-F site, and Remote Operation Center (ROC) inside KASI is designed for remote access and the automatic tracking and control system which are the main operation concept of ARGO system. To accomplish remote operation, we are considering remote access to ARGO-F and ARGO-M from ROC. The mobile-phone service allows us to access the ARGO-F remotely and to control the system in an emergency. To implement fully automatic tracking and control function in ARGO-F, we have investigated and described the requirements about the automatic aircraft detection system and the various meteorological sensors. This paper addresses the requirements of ARGO Operation System.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.2
• /
• pp.187-196
• /
• 1997

This paper presents a semi-automatic methodology to synthesize executable digital controller saftware in a multi-loop control system. A digital controller is described by a task graph and end-to-end timing requirements. A task graph denotes the software structure of the controller, and the end-to-end requirements establish timing relationships between external inputs and outputs. Our approach translates the end-to-end requirements into a set of task attributes such as task periods and deadlines using nonlinear optimization techniques. Such attributes are essential for control engineers to implement control programs and schedule them in a control system with limited resources. In current engineering practice, human programmers manually derive those attributes in an ad hoc manner: they often resort to radical over-sampling to safely guarantee the given timing requirements, and thus render the resultant system poorly utilized. After task-specific attributes are derived, the tasks are scheduled on a single CPU and the compiled kernel is synthesized. We illustrate this process with a non-trivial servo motor control system.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1360-1364
• /
• 2004

This paper propose an extended model for role-permission assignment based on locations called "Enhanced Role-Based Access Control (ERBAC03)". The proposed model is built upon the well-known RBAC model. Assigning permissions to role is considered too complex activity to accomplish directly. Instead we advocate breaking down this process into a number of steps. The concept of jobs and tasks is specifically introduced to facilitate role-permission assignment into a series of smaller steps. This model is suitable for any large organization that has many branches. Each branch consists of many users who work in difference roles. An administration tool has been developed to assist administrators with the administration of separation of duty requirements. It demonstrates how the specification of static requirements can be done based on "conflicting entities" paradigm. Static separation of duty requirements must be enforced in the administration environment. Finally, we illustrate how the ERBAC03 prototype is used to administer the separation of duty requirements.

• Journal of KIISE:Software and Applications
• /
• v.35 no.12
• /
• pp.731-740
• /
• 2008

A railway control system is one of the typical safety-critical systems. It is required to use formal methods for the requirements specification and verification in order to develop the global-standard railway control systems based on the computer systems. In this paper, we develop a guideline for requirements specification using formal methods, and present a case study of the development of a computer-based railway control system through the application of the proposed guideline. We use the Statechart and the Z method for the formal requirements specifications and verify the consistency and completeness of the formal specifications of the requirements.

• Journal of Astronomy and Space Sciences
• /
• v.36 no.4
• /
• pp.235-248
• /
• 2019

This paper suggests a relative orbit control strategy for the CubeSat Astronomy by NASA and Yonsei using Virtual Telescope Alignment eXperiment (CANYVAL-X) mission whose main goal is to demonstrate an essential technique, which is an arrangement among two satellites and a specific celestial object, referred to as inertial alignment, for a next-generation virtual space telescope. The inertial alignment system is a relative orbit control system and has requirements for the relative state. Through the proposed orbit control strategy, consisting of separation, proximity keeping, and reconfiguration, the requirements will be satisfied. The separation direction of the two CubeSats with respect to the orbital plane is decided to provide advantageous initial condition to the orbit controller. Proximity keeping is accomplished by differential atmospheric drag control (DADC), which generates acceleration by changing the spacecraft's effective cross section via attitude control rather than consuming propellant. Reconfiguration is performed to meet the requirements after proximity keeping. Numerical simulations show that the requirements can be satisfied by the relative orbit control strategy. Furthermore, through numerical simulations, it is demonstrated that the inertial alignment can be achieved. A beacon signal had been received for several months after the launch; however, we have lost the signal at present.

• International Journal of Automotive Technology
• /
• v.1 no.2
• /
• pp.61-69
• /
• 2000

This paper will address the basic requirements for realizing a stop and go cruise control system. Issues discussed comprise: functional, sensor and basic HMI requirements, primary characterization of naturalistic stop & go driving, and the basic approach of the transformation of situational knowledge in an elementary controller.

• Journal of the Korean Society of Systems Engineering
• /
• v.13 no.2
• /
• pp.18-25
• /
• 2017

The use of unmanned combat systems is of interest for future battlefield. Advanced techniques are being actively studied to build fully autonomous unmanned systems. However, there are technical, ethical and legal limitations for the fully autonomous unmanned combat systems. In addition, a remote controlled system is necessary so far in order to prepare for situations where fully autonomous unmanned systems fail to function properly. Thus, a procedure of developing operational requirements in system level is proposed and interface requirements of unmanned combat vehicles for remote control are described in this study.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1156_1158
• /
• 2009

A train control system(TCS) becomes a large scale and complex as other computer based control systems. So, it is necessary to manage rigorously system requirements specification of the train control system at the early phase. This paper describes Use Cases and activity diagrams of the TCS functions requirements of TCS. Basic functions of the train control system suggested refer to IEC62290-1. And the basic functions includes train operation without a driver.