System Functional Requirements Research Articles

監視制御システム向けアプリケーションフレームワーク

This paper describes GRASS, an object-oriented framework for SCADA (Supervisory Control And Data Acquisition) systems. The proposed framework consists of class libraries and tools, that support development of SCADA system software. The basic functional requirements of SCADA systems are similar, regardless of the particular application field, so substantial software sharing is possible. Nevertheless, productivity of SCADA software is impeded by dependence on details of the target system. The task of configuring the SCADA software for each target system is complex, typically involving manual input of a lot of system description data. GRASS simplifies this task by automatically generating system description data and providing editing tools for subsequent customization.

Applicability of SIGNAL in safety critical system development

This paper concerns the specification of functional and safety requirements of a safety critical system independently, and subsequent validation of the integrated requirements in the synchronous data-flow formalism SIGNAL. The SIGNAL language provides a unified framework for hierarchical development of systems by refinement of specifications. Validation of specifications can be realised through a formal calculus based on the semantics of the language or through functional simulation. In this context, the research reported attempts safety management in critical real-time systems in an application–independent manner. This is based on the possibility of identifying low and high risk states in a system and expressing its functional behaviour as transitions between pairs of states of different levels of risk. Safety requirements become conditions prohibiting low to high risk transitions, or forcing high to low risk transitions in a timely manner. A safety module, which is in charge of ensuring that these conditions are observed at run-time, is developed in SIGNAL to explore the applicability of the SIGNAL language to safety-critical design and to establish both the feasibility and the extent of managing safety concerns in an application–independent manner.

A framework of a concurrent process planning system for mold manufacturing

This paper presents a research on the development of a computer-based framework that supports concurrent mold manufacturing process planning. The practical goal of this research is three-fold: (1) to develop a systematic and concurrent mold manufacturing process planning model, (2) to develop a computer-based mold manufacturing process planning system based on the concurrent model, and (3) to develop knowledge bases to assist in concurrent type of mold manufacturing process planning that accommodates mold development concerns, as well as the requirements of the products. The approach of this work includes steps of (1) modeling and reengineering concurrent mold manufacturing process planning, (2) analysis of system functional requirements, (3) system framework design, and (4) system modeling and implementation. The results of this research will facilitate the rationalization and automation of the mold development process planning, thus improving the efficiency and quality, and also reducing the cost of molding product and process development.

Scientific applications of robotic systems on planetary missions

This paper focusses on Mars landing missions. It gives a brief survey of past international missions and outlines the objectives of the European science community concerning Mars surface exploration. It reviews the studies performed by the ESA science programme in the past (Marsnet, InterMarsnet), culminating in the current efforts to prepare the Mars Express mission for launch in 2003. From the scientific objectives, the functional and performance requirements of robotic systems are derived which are perceived as essential for unmanned Mars surface exploration. The very severe constraints on robot systems from the launch, cruise, and Mars surface environment are described as well as the need for extremely lightweight and low-power solutions with very high science support efficiency. Five typical classes of A&R systems for Mars exploration are specifically identified: simple masts or booms, automation systems for drilling and sample handling, micro rovers for instrument deployment, mini rovers for long range exploration, and “mole” type penetrators. Of these, the drilling/sample handling devices and the micro rovers are covered in more detail, with references to papers describing their developments.

Development of a computer-aided concurrent net shape product and process development environment

This paper presents a systematic approach to developing a collaborative environment for computer-aided concurrent net shape product and process development. This approach includes the steps of (1) conventional development process analysis, (2) development process re-engineering, (3) computer-based system functional requirements analysis, (4) system framework design, and (5) system modeling, integration and implementation. This environment can support concurrent net shape product and process development by providing and integrating functions of product data management, process management and development advisory tools. The results of this research will facilitate the rationalization and automation of net shape product and process development and thus improve the efficiency and quality, and reduce the cost of net shape product development. IDEF structural analysis methodology was employed to capture the characteristics of net shape product and process development process. The concept of concurrent engineering was used to re-engineer the development process. The technology of system engineering was used to design the computer-aided system framework. Object-oriented analysis, modeling and design methodology, knowledge engineering and data engineering techniques were employed for system modeling and implementation.

CRITICAL PROCESS ASSESSMENT TOOL (CPAT) FOR ACQUISITION REFORM IN DOD

AbstractAcquisition reform within the U.S. Department of Defense (DoD) has induced a wide variety of innovative engineering methodologies on the part of Air Force agencies such as the Space and Missile Systems Center (SMC) in El Segundo, CA to minimize government risk. One of these methodologies is a set of Critical Process Assessment Tools (CPATs) being developed to support project officers and project engineers: (1) in preparing Requests for Proposals (RFPs), (2) for subsequent source selection or factfinding, and (3) to participate in or review contract execution after contract award. CPATs are applicable to processes that, because of risk, are considered to be critical to execution of the involved contract. The Systems Engineering CPAT (SE‐CPAT) is the overriding element in the set since it is most likely to be critical to the success of a contract when new military or other system functional requirements are to be levied or requirements allocations and/or design must be changed for some reason. Furthermore, the SE‐CPAT serves as the integrator of other multidisciplinary engineering CPATs acting under the Integrated Product Development environment. The SE‐CPAT described in this paper, and available on the Internet, identifies a menu of objectives and other inputs to a RFP, factors and standards for source selection, and key questions for conducting technical evaluations and factfinding, and post‐contract award reviews. Throughout the paper selected SE‐CPAT excerpts are provided.

A partitioning technique for concurrent software design

Software partitioning is the process of mapping software functional requirements into a set of program modules for implementation. This paper analyzes concurrent software design techniques that are based on structured analysis and design (SA/SD) in order to highlight their potential and their shortcomings. A partitioning technique based on the analysis of the data and control flow of a system's functional requirements is proposed next. This technique, called the Concurrent Software Design Technique (CSDT), extends the current SA/SD techniques by identifying concurrent independent tasks for implementation in multitasking or multiprocessing environments. Finally, the application of this technique is illustrated through an example.

The measured performance of personal computer operating systems

This article presents a comparative study of the performance of three operating systems that run on the personal computer architecture derived form the IBM-PC. The operating systems, Windows for Workgroups, Windows NT, and NetBSD (a freely available variant of the UNIX operating system), cover a broad range of system functionality and user requirements, from a single-address-space model to full protection with preemptive multitasking. Our measurements are enable by hardware counters in Intel's Pentium processor that permit measurement of a broad range of processor events including instruction counts and on-chip cache miss counts. We use both microbenchmarks, which expose specific difference between the systems, and application workloads, which provide an indication of expected end-to-end performance. Our microbenchmark results show that accessing system functionality is often more expensive in Windows for Workgroups than in the other two systems due to frequent changes in machine mode and the use of system call hooks. When running native applications, Windows NT is more efficient than Windows, but it incurs overhead similar to that of a microkernel, since its application interface (the Win32 API) is implemented as a user-level server. Overall, system functionality can be accessed most efficiently in NetBSD; we attribute this to its monolithic structure and to the absence of the complications created by hardware backward-compatibility requirements in the other systems. Measurements of application performance show that although the impact of these differences is significant in terms of instruction counts and other hardware events (often a factor of 2 to 7 difference between the systems), overall performance is sometimes determined by the functionality provided by specific subsystems, such as the graphics subsystem or the file system buffer cache.

Non-interference through determinism*

The standard approach to the specification of a secure system is to present a (usually state-based) abstract security model separately from the specification of the system's functional requirements, and establishing a correspondence between the two s

The Impact of Software Timing Correctness on Systems Safety

Whilst increasingly the importance of the timing correctness of software (and of systems in general) is being recognised, in truth this aspect of design is not yet receiving full attention. Often the full extent of timing problems are not understood, and software engineering tools to support comprehensive timing analysis are not commercially available. Even in the case of systems that must be licenced before use, the licensing procedures do not normally study timing correctness systematically. The situation is particularly serious with systems that are based on intelligent automation techniques because of such systems’ intrinsic non-deterministic behaviour This paper starts with examples of where timing errors (or timing inconsistencies) may cause major problems in a system's functioning. These examples lead to the conclusion that timing problems cannot be handled separately from considerations of algorithms, other software components, and the application itself. This relationship between timing and system's behaviour leads to the suggestion that it is necessary to have a joint description, and an analysis of, a system's functional and non-functional requirements. The timing analysis involved should also be iterated around at each stage of a system's lifecycle. To this end the paper concludes with a description of a formal method and a new CASE tool that supports the designer in studying and/or verifying the timing correctness of a proposed system during all stages in its design and implementation

Distributed control of assembly cells based on virtual manufacturing device model

This research paper presents the results of the joint research project between the Technical University of München (IWB), and the CIM RL of the Computer and Automation Research Institute, Hungary. The project involves the modular design of information system for shop-floor control of assembly applications. The work is carried out in a co-operation with IWB, and the tests are initiated at both places, i.e. at the IWB and also at the Computer and Automation Research Institute, within the environment of the CIM RL. The different brand robots, robotcontrollers and intelligent shop-floor devices, e.g. laser sensors, terminals are essential elements for automated production facilities, and their integration to a unified system is the key aspect of this project. This article describes a test configuration where the CIM elements are integrated and tested for functional system requirements for future’s real industrial applications.

Tolerancing a solid model with a kinematic formulation

The 3D analysis of tolerances is one of the critical functional requirements of solid-modelling systems which is most lacking at the present time. 3D tolerance analysis is most difficult to carry out by hand when it involves geometrical tolerances. A computerized 3D tolerance analysis is therefore needed, and an appropriate tolerancing model must be devised. The paper first acknowledges the kinematic nature of tolerance-chain analysis. A kinematic formulation of full 3D dimensional and geometrical tolerances is then proposed. The scheme represents all tolerances within a kinematic model, which is compatible with existing standards such as ansi y14.5m. The semantics of tolerances is respected, as tolerances are automatically interpreted to yield tolerance zones and datum reference frames. A tolerance chain is modelled as a kinematic chain, thus enabling multiple tolerances to be manipulated to solve 3D tolerance-chain analysis problems. The implementation of the modelling concept on an exact solid modeller is described. An application of the tolerancing model to the visualization of tolerance zones is also shown.

Wide area network performance modeling of distributed energy management systems

A distributed energy management system consists of networked hardware and software capable of monitoring and controlling the operations of an electric utility. When several of these distributed systems are connected to each other via wide area network connections, then a truly geographically distributed environment exists where data between systems can be shared. Heavy communication network loads and transit time constraints on these large amounts of shared data are significant design considerations, especially in light of the fact that most power utilities have existing private networks or use leased voice grade circuits. Modeling of the wide area network aspects of interconnected energy management systems was seen as a way to identify potential communications problem areas between systems early in the design process. Modeling would also help verify that the hardware and software designs would accommodate the communications load and ensure that transit times were within the system's functional requirements. System stress case data was used in each model to simulate a worst-case data acquisition and dissemination environment. This paper describes the modeled configuration and provides specific details about the system simulation techniques used and the conclusions provided by the model to estimate transit times and line rates for WAN connections.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

DoD legacy systems

As with most large organizations, the Department of Defense has both strategic and economic needs to capitalize on and to consolidate existing information systems. This paper reports on a framework currently being used to reverse engineer selected legacy information systems in DoD's heterogeneous environment. This generic approach was developed to recover organizational business rules, business domain information, system functional requirements, functional dependencies, and system data architectures, largely in the form of normalized logical data models. We are applying the approach as a series of pilot studies on systems ranging from those using home grown languages and database management systems developed during the late 1960's to those using high order languages and commercial network database management systems. These pilot studies are being used to validate and refine the framework with real-life systems; to develop a baseline approach for reverse engineering DoD legacy information systems; and to scope and estimate future system re-engineering costs. Furthermore, the results of these projects will help to determine the economic viability of re-engineering, reverse, and forward engineering efforts for these legacy systems.

A simple method for phased mission analysis

In a large-scale system such as chemical and nuclear plants, the system function requirement changes during its operation and its component must also play various roles depending on the system state. Since the logical relation between the system and its components changes during the system operation, the Phased Mission Analysis (PMA) must be introduced into their reliability analysis. The basic event transformation method in PMA can evaluate their reliability exactly, but it makes the analysis more complicated and time-cosuming. This paper develops a new, simple, and practical method for PMA. A novel component condition expression is proposed, which can express time requirements explicity. The logical operations of conditions for a component are transformed into the modification of time parameters in its expression. Event sequence conditions are obtained as logical OR of logical AND combinations of the proposed component condition expressions and their probabilities can be easily evaluated based on them. Illustrative examples show the effectiveness and merits of the proposed method compared with the dual tree method in Event Tree Analysis and the basic event transformation method in PMA. Especially, in an example of an emergency core cooling system (ECCS), the proposed method (1) can obtain mission failure conditions in a compact from of 7 terms while 70 minimal cut sets are obtained by the basic event transformations method, and (2) can obtain the mission unreliability in an analytical form.

Core Functional Requirements for Fiscal Management System

Core Functional Requirements for Fiscal Management System

APPLICATIONS OF MODERN SYSTEMS ANALYSIS PARADIGMS TO THE DEVELOPMENT OF COMPLEX SYSTEMS

AbstractThe overwhelming volume of requirements and specifications associated with large complex multi‐disciplinary system development projects pose exceptional challenges to project engineers in their efforts to track and manage the hardware design response to the requirements and specifications. Previous systems engineering approaches using available methodologies and automated computer tools have been increasingly difficult to apply as the project complexity grows. Without effective methodologies and tools ensuring that system functional requirements are accurately interpreted and flowed down to the specification level has been difficult. Likewise, the allocation of functions to the architectural components, assemblies, and software including the interfaces among interacting systems has been hampered by inadequacy of conventional tools. This traceability extends to the identification of verification requirements associated with all elements of the system.The demand for increasingly complex systems, coupled by the ever‐increasing sophistication of available supporting engineering and management tools, has spawned a variety of modern methodologies for addressing complex development tasks. These new paradigms, aided by powerful computer‐based software tools, provide a structured development framework to: Instill a disciplined focus on system engineering based on requirements Establish a comprehensive, unambiguous path of trace‐ability from top‐level requirements to detailed design Provide a common means for communicating complex system behavior to all program participants via graphical depictions Develop a platform for the systematic support of the verification and test planning activities Analyze the failure propagation behavior of the system for assessment of multiple failure modes and effects, safety and hazards analyses, redundancy management and failure tolerance Create a simulation environment to study system behavior for analysis of performance, interfaces, and anomalies given a variety of hypothetical operational scenarios. This paper discusses the application of such a methodology, known as Enhanced Modern Structured Analysis (EMSA), which is being used in the analysis of the Space Station Freedom. The EMSA method has been derived from the methodologies of leading experts in the field of systems analysis, with suitable enhancements which were found necessary to accommodate the Space Station Program needs. The software to support this particular analysis is the RDD‐100 (TM) package from Ascent Logic Corporation, as well as the Failure Environment Analysis Tool (FEAT) developed by Lockheed Engineering and Sciences Company. The hardware platform is an Apple Mactinosh IIfx(TM).Due to the prolific nature of general systems analysis, coupled with the power of a sophisticated computer platform and the flexibility of the methodology, this paradigm is recognized as having a wide applicability for analysis.

Section 1. Functional Requirements for an ICONCLASS Retrieval System

Section 1. Functional Requirements for an ICONCLASS Retrieval System

Integral: Petri-net approach to distributed software development

As the architecture of modern software systems continues to evolve in a distributed fashion, the development of such systems becomes increasingly complex, which requires the integration of more sophisticated specification techniques, tools, and procedures into the conventional methodology. An essential capability of an integrated software development environment is a formal specification method to capture effectively the system's functional requirements as well as its performance requirements. A validation and verification (V&V) system based on a formal specification method is of paramount importance to the development and maintenance of distributed systems. There has been recent interest in integrating software techniques and tools at the specification level. It is also noted that an effective way of achieving such integration is by using wide-spectrum specification techniques. In view of these points, an integrated V&V system, called Integral, is presented that provides comprehensive and homogeneous analysis capabilities to both specification and testing phases of the life-cycle of distributed software systems. The underlying software model that supports various V&V activities in Integral is primarily based on Petri nets and is intended to be wide spectrum. The ultimate goal of this research is to demonstrate to the software industry, domestic or foreign, the availability and applicability of a new Petri-net-based software development paradigm. Integral is a prototype V&V system to support such a paradigm.

Some early achievements in landing guidance using mechanically scanned pulse-encoded beams

A microwave scanning beam landing system from the 1950s and 1960s is still operating routinely. It depends on airborne reception of pulse-coded signals from mechanically scanned antennas. Military versions include the US Navy's C-Scan for carrier landings and the Tactical Instrument Landing System used in Sweden. Other sets, called microwave scanning beam landing systems, serve Space Shuttle orbiters. System concepts and functional hardware requirements were tested extensively by on-ground and flight procedures. Both the US Navy and Sweden purchased operational equipments in 1969.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>